Biology is an experimental science. "Biology Curriculum Standard" puts forward that "scientific inquiry is the breakthrough to change students' learning style". In classroom teaching, some demonstration experiments and students' experiments are changed into inquiry experiments to guide students to think more, think more and see more, break the mindset, realize innovative learning and cultivate innovative ability. Observation is a basic activity of inquiry experiment, and scientific observation is the premise of learning biological knowledge well. Scientific observation, as a kind of thinking activity, is to link the present observation with the experience gained from past observation and process and transform it. Scientific observation not only attaches importance to qualitative observation and grasps the image, structure, process and characteristics of things, but also attaches importance to quantitative observation, analyzes its quantitative relationship and synthesizes its nature and characteristics. In biology teaching, it is necessary to cultivate students' observation interest and in-depth and meticulous observation quality, and form students' ability to find, ask and analyze problems in observation. For example, when studying the section "the influence of light on the life of rat girl", the author arranged for students to catch rat girl themselves in advance. In the process of catching mice and girls by themselves, students found and raised many questions through their own observation, and came to class with doubts and questions, which improved their interest in learning and enthusiasm for observation. In class, the author asked the students to observe in groups, and the group members worked together. Someone is responsible for recording, someone is responsible for operation, someone is responsible for punctuality, and someone is responsible for observing and counting. Each group earnestly carried out observation activities and reported their observation results in class. We analyzed, discussed and communicated together, and came to the conclusion that the rat girl likes to live in a dark environment. On this basis, guide the students to continue to observe and ask a new question: Since light affects the life of the mouse wife, does the dryness and wetness of the soil also affect the life of the mouse wife? Next, guide students to design their own experimental schemes and steps, carry out their own observation activities and analyze observation phenomena, and combine observation and analysis to draw a conclusion.