国际科学教育的蓬勃发展促使我国新一轮课程改革的进行。在课程改革中，教科书改革是一个重要的环节，是将改革的目标具体化、实现课程改革目标的重要载体。所以，教科书的开发一定要适应学生的发展。教科书的难度研究非常有必要，教科书难度的国际比较非常有必要。本文对中国、澳大利亚和法国三国的高中生物教科书分别在广度、深度和难度三个方面详细进行了量化比较和文本分析，并针对我国高中生物教科书的使用和编写提出建议。本研究采用的研究工具分别是高中生物学教科书广度分析工具和高中生物学教科书深度分析工具。最终，利用教科书难度计算模型：N=G×S，得出各国高中生物学教科书的难度值。研究结果表明：（1） 教科书难度方面：中国、澳大利亚和法国高中生物学教科书相比较，澳大利亚教科书的难度值最大，中国教科书次之，法国教科书的难度值最小。（2） 教科书广度方面：澳大利亚高中生物学教科书的广度值最大，中国教科书次之，法国教科书的广度值最小。这说明澳大利亚教科书中出现的符合研究工具计分规则的“术语”的个数最多，中国教科书次之，法国教科书最少。（3） 教科书深度方面：中国高中生物学教科书的深度值最大，法国教科书次之，澳大利亚教科书的深度值最小。这说明：整体来说，中国教科书具有更多的高中学段和大学学段的核心概念或者具有更少的幼儿园学段、小学学段和初中学段的核心概念。

The vigorous development of the international scientific education promotes a new round of curriculum reform in our country . In the curriculum reform, the textbook reform, which is the specific of the goal of the reform, is an important link. The textbook is the important carrier of achieving the curriculum reform goal. Therefore, the textbook development must adapt to the development of students. The research of the difficulty of the textbook is very necessary. The difficulty of the international comparison is very necessary. In this paper, I have carried the detailed quantitative comparison and qualitative analysis on the breadth, depth and difficulty of the three types of biology textbooks in China, Australia and France. And then, I will put forward proposals to the using and writing of the textbooks. In this study, the tools of the research are the analysis tool of high school biology textbooks’ breadth and the analysis tool of high school biology textbooks’ depth. Ultimately, using the computing model of the textbooks’ difficulty: N = G × S, We can eventually get the difficulty value of the biology textbooks in all the country's high school.The study results show that:(1) Textbooks’ difficulty: Compared to the three types of high school biology textbooks in China, Australia and France ,I find that the difficulty of textbooks in Australia is the biggest, followed by the textbooks in China, and the difficulty of textbooks in France is minimum.(2) Textbooks’ breadth: The breadth of the high school biology textbooks in Australian is the biggest, followed by the textbooks in France .And the breadth of the Chinese textbooks is minimum. The Australian textbooks have the most terms, that meet the requirement of the tool. The Chinese textbooks have more. And the French textbooks have the least. (3) Textbooks’ depth: The depth of the high school biology textbooks in China is the biggest, followed by France, and then Australia. This shows that the Chinese textbooks have more important concepts in high school and the university .Or they have fewer important concepts in kindergarten, primary school or junior high school.