With the development of information technology, online and offline mixed teaching mode has become a new education mode and is widely used. Taking the course of "Introduction to Computer cience" as an example, this paper studies and analyzes the construction foundation and construction scheme of online and offline hybrid teaching mode. This paper expounds in detail the reform of teaching concept, deepening of teaching content, improvement of teaching methods and reform of examination methods in the process of online and offline hybrid teaching design and implementation. Finally, it summarizes the good application prospect and areas to be improved of this hybrid teaching mode in teaching practice.