Enabling students to learn about science is essential for science education. Students are expected to not only gain scientific knowledge but also need to develop a deep understanding of science. One approach to equipping students with a sense of science is to present science as a living collective human enterprise. As essential educational resources, science textbooks are powerful supportive tools for helping students be aware of the tentative, historical, and humanistic features of science. This study aims to develop and validate a comprehensive analytical framework for examining how a science textbook enables students to understand science and scientists through scientists' portrayals. The final analytical framework comprises five themes and 13 dimensions concerning scientists and their work, including the textbook's representation method (i.e., format and role of representation), scientists' background (i.e., personal and social background), scientists' work-related features (i.e., motivation for doing research, research methods, and way of working), scientists' achievements (i.e., type, evaluation, and influence), and educational values of scientists and their work (i.e., scientific thinking, scientific attitudes, and social responsibility). The analysis results of an American high school science textbook indicate that the framework developed is feasible to cover all the desired scientist-related elements and evaluate the extent of scientists' portrayals presented in the textbooks. In addition, the results also revealed that this textbook is inadequate in providing students with a comprehensive understanding of science and scientists via its portrayals of scientists.