For the reform of teaching materials, for a long time, people mainly pay attention to the increase or decrease of the content of teaching materials, but seldom pay attention to the structure and content of teaching materials. However, in the modern society where knowledge and information are increasing rapidly, textbooks can not cover everything, but must constantly enrich advanced scientific knowledge, which is obviously contradictory. However, in order to solve the contradiction, it is not enough to simply add or delete the content