1. Introduction: Why Does the Choice of AI Model Matter?
In the practical application of BelinDoc, users often face two core questions:
- Which model should I choose for translation?
- Which model is best suited for my specific document type?
Indeed, AI translation models are iterating rapidly, and the translation styles of different models vary significantly. When choosing a model, should we rely solely on "newer/more expensive" as the standard?
To help you find the most suitable translation model on BelinDoc, we conducted a horizontal benchmark of the mainstream models available on our platform, including GPT-4.1 Mini, GPT-5 Mini, Gemini 2.5 Flash, and Gemini 2.5 Pro. We hope this provides a valuable reference for your workflow.
2. Evaluation Design: Ensuring Fairness
Test Scenarios
We selected 5 of the most common professional document scenarios on BelinDoc and prepared a typical English sample for each, covering: Architecture/Engineering, Medical Research, Microelectronics, Science Fiction, and Mathematics.
Unified Prompt
To minimize the interference of instructions on the results, all models used the exact same system prompt:
Please translate and rewrite the following English article into accessible, engaging, and fluent Simplified Chinese.
Core Requirements:
- Accuracy First: Core facts, data, and logic must be perfectly aligned with the source.
- Fluency: Prioritize authentic Chinese sentence structures. Break down long English sentences into natural short Chinese phrases.
- Standard Terminology: Use industry-recognized standard translations for technical terms (e.g., `LLM` -> `大语言模型`).
- Formatting: Preserve the original Markdown formatting (headers, bold, italics).
Metrics & Weighting
We invited linguists with TEM-8 (Test for English Majors-Band 8) certification to subjectively score the results based on the following criteria:
| Metric | Weight | Description |
|---|---|---|
| Accuracy | 40% | Semantic integrity; no missed or mistranslated text. |
| Fluency | 30% | Natural and smooth Chinese phrasing. |
| Terminology | 20% | Consistency in technical/professional jargon. |
| Style | 10% | Fidelity to the original tone (formal/creative). |
Note: This review focuses on English-to-Chinese translation accuracy and fluency. Comparisons for Japanese, Russian, and Korean will be released in future updates.
3. The Benchmark: 5 Core Scenarios
🏗️ Scenario 1: Architecture / Civil Engineering
Source: The foundation slab, with a thickness of 1.2 meters, must withstand a vertical load of 2,500 kilonewtons per column while maintaining less than 5 millimeters of settlement under full load conditions.
Verdict & Analysis:
| Model | Speed | Accuracy (40%) | Fluency (30%) | Professionalism (20%) | Overall (5.0) | Expert Commentary |
|---|---|---|---|---|---|---|
| Gemini 2.0 Flash | ⏰ 2s | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | 4.0 | Accurate and concise, but slightly too colloquial for engineering reports. |
| Gemini 2.5 Flash | ⏰ 8s | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐½ | 4.3 | Solid performance. Uses professional terms like "荷载" (Load) and "工况" (Working conditions) correctly. |
| Gemini 2.5 Pro | ⏰ 19s | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐⭐ | 4.7 | Best Performer. The terminology and engineering style match perfectly. It reads like a professional report. |
| GPT-4.1 Mini | ⏰ 2s | ⭐⭐⭐½ | ⭐⭐⭐ | ⭐⭐⭐ | 3.4 | Excessive sentence splitting hurt the logical flow; reads more like technical notes than a formal translation. |
| GPT-5 Mini | ⏰ 15s | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐½ | 4.6 | Accurate and natural. Terms are stable. Very close to high-quality human translation, just slightly less formal than Gemini Pro. |
Summary: For engineering documents where professionalism is paramount, Gemini 2.5 Pro is the top choice. GPT-5 Mini follows
closely, making it an excellent choice balancing quality and natural flow.
🧬 Scenario 2: Medical Research Paper
Source: In a randomized clinical trial involving 320 patients, the combination therapy reduced the incidence of postoperative infection by 37% compared to the control group.
Verdict & Analysis:
| Model | Accuracy | Terminology | Naturalness | Academic Norms | Overall | Expert Commentary |
|---|---|---|---|---|---|---|
| Gemini 2.0 Flash | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | Accurate, but the phrasing for "involving" was slightly colloquial. | |
| Gemini 2.5 Flash | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐½ | Better tone. Used "涉及" (involving) which fits well, steady and natural. | |
| Gemini 2.5 Pro | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | Tied for Best. Used "纳入" (enrolled/included) which is highly professional. Formal style fits SCI papers perfectly. | |
| GPT-4.1 Mini | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | Accurate but brief; connective phrasing was slightly weak. | |
| GPT-5 Mini | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | Tied for Best. Precise and logically smooth. Fits the medical register perfectly, approaching human translator standards. |
Summary: For medical papers, Gemini 2.5 Pro and GPT-5 Mini are neck and neck, both producing publication-ready translations. Gemini Pro sounds more "academic," while GPT-5 Mini has a slight edge in sentence fluidity.
⚙️ Scenario 3: Microelectronics Manual
Source: When the input voltage exceeds 5.5V, the low-dropout regulator automatically switches to bypass mode, ensuring continuous power delivery while protecting the downstream MOSFET from overvoltage stress.
Verdict & Analysis:
| Model | Accuracy | Professionalism | Naturalness | Overall (5.0) | Expert Commentary |
|---|---|---|---|---|---|
| Gemini 2.0 Flash | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | 4.2 | Technical points correct, but the word choice for "stress" was less formal than "damage/harm." |
| Gemini 2.5 Flash | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐½ | 4.3 | Natural expression, but simplified the logic structure slightly too much. |
| Gemini 2.5 Pro | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | 5.0 | Tied for Best. Professional, formal, logical. adhere strictly to engineering documentation norms. |
| GPT-4.1 Mini | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐½ | 4.7 | Accurate. Correctly used "Linear Regulator" for specificity. |
| GPT-5 Mini | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | 5.0 | Tied for Best. Perfect terminology—it even proactively added the acronym "(LDO)" which wasn't in the source, showing deep domain knowledge. |
Summary: In microelectronics, GPT-5 Mini and Gemini 2.5 Pro excel. GPT-5 Mini is the top choice for technical manuals as it intelligently supplements acronyms like "LDO," demonstrating superior context understanding.
🚀 Scenario 4: Science Fiction Literature
Source: At precisely 02:47 a.m., the last transmission from Earth echoed across the void, carrying a fragment of music that no one had heard in a thousand years.
Verdict & Analysis:
| Model | Accuracy | Literary Style | Flow | Imagery | Overall (5.0) | Expert Commentary |
|---|---|---|---|---|---|---|
| Gemini 2.0 Flash | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐ | 3.6 | Accurate but flat. Felt like a direct translation rather than a story. |
| Gemini 2.5 Flash | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐ | 4.3 | Vivid vocabulary. Translated "fragment of music" poetically as "musical movement fragment." |
| Gemini 2.5 Pro | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | 5.0 | Tied for Best. Precise and atmospheric. Words like "echoed" (回响) created a great sense of space. |
| GPT-4.1 Mini | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | 4.2 | Clear and natural, but slightly lacked the immersive quality of the top models. |
| GPT-5 Mini | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | 5.0 | Tied for Best. Excellent rhythm. The sentence structure heightened the sense of urgency and emotion. |
Summary: For literary translation, GPT-5 Mini and Gemini 2.5 Pro both beautifully restore the imagery and aesthetic of the original text. GPT-5 Mini has a slight advantage in rhythmic flow, making it ideal for creative writing.
🔢 Scenario 5: Mathematics Paper
Source: For any continuous function f(x) defined on [0, 1], the mean value theorem guarantees the existence of at least one point c ∈ (0, 1) such that f′(c) = f(1) − f(0).
Verdict & Analysis:
| Model | Accuracy | Math Terminology | Flow | Logic | Overall (5.0) | Expert Commentary |
|---|---|---|---|---|---|---|
| Gemini 2.0 Flash | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | 4.0 | Accurate, but lacked the formal tone required for math papers. |
| Gemini 2.5 Flash | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐½ | 4.5 | More academic. Correctly used terms like "open interval" clearly. |
| Gemini 2.5 Pro | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | 5.0 | Best Performer. It proactively added "(Lagrange)" before "mean value theorem," making it professionally precise. |
| GPT-4.1 Mini | ⭐⭐⭐⭐½ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | 4.2 | Concise and accurate, but lacked the academic polish of the Pro model. |
| GPT-5 Mini | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | 4.9 | Concise, accurate, logical. Very close to human translation, only missed the extra context addition that Gemini Pro provided. |
Summary: In rigorous mathematical contexts, accuracy is high across the board. However, Gemini 2.5 Pro is the optimal choice for its ability to supplement professional context (like adding "Lagrange"), followed closely by the reliable GPT-5 Mini.
4. Comprehensive Comparison & Recommendations
After detailed testing across five scenarios, the distinct personalities of each model have emerged.
Model Cheat Sheet
| Model | Core Characteristic | Best Use Cases | Pros | Cons |
|---|---|---|---|---|
| Gemini 2.0 Flash | Fast Response, Basic Accuracy | Previews, Informal docs, Summaries | Fastest speed, handles numbers/units well. | Weak in professional tone and literary style. |
| Gemini 2.5 Flash | Balanced, Standard Terms | Tech specs, Manuals, Initial reports | Better terminology than 2.0, clear logic. | Lacks literary flair; average handling of long sentences. |
| Gemini 2.5 Pro | Formal & Rigorous | Engineering reports, Academic papers, Contracts | Extremely standard terminology, rigorous logic. | Relatively slower translation speed. |
| GPT-4.1 Mini | Fast & Fluid, Generalist | Blogs, Pop-science, Light reading | Fast, natural language, good symbol handling. | Lacks professional depth; occasional precision drops in complex logic. |
| GPT-5 Mini | The All-Rounder | High-level Research, Literature, Marketing | Most natural flow, rigorous logic, balances style and accuracy. | Moderate speed. |
BelinDoc’s Recommendation Guide
To help you choose quickly:
- Do you want the highest quality and most natural flow?
- 🥇 Top Pick: GPT-5 Mini. It is the "all-rounder" closest to high-quality human translation, especially for texts requiring stylistic nuance.
- Translating highly technical or academic papers?
- 🥈 Runner-up: Gemini 2.5 Pro. It is the "safe bet" for Engineering, Medicine, and Science, offering impeccable terminology and formal tone.
- Balancing cost and stability?
- 👍 Recommended: GPT-4.1 Mini. Fast and stable, sufficient for most daily document needs.
- Just need a quick preview or summary?
- ⚡ Fastest: Gemini 2.5 Flash. Provides the quickest turnaround while maintaining basic accuracy.
5. Conclusion: The Era of "On-Demand" Selection
This benchmark demonstrates that different AI models have developed distinct "personalities." Some are rigorous like scholars, others are expressive like novelists.
It is important to note that AI translation can have a degree of randomness. This review serves as a general reference. At BelinDoc, we have pre-configured optimized prompts and terminology bases for different models and industry scenarios to ensure the best possible results for your specific niche.
In the future, the competition won't just be about "who is faster," but "who understands your specific needs better." Stay tuned for our next review, where we will cover multi-language comparisons.
