Engineering geology course is with the characteristics of comprehensive, theoretical and practical. Complex engineering problems with complicated geological problems together, often make the students do not know how to start, the understanding of the problem can only stay on the surface. However, engineering geology, as an important major basic course in major of water conservancy and hydropower engineering, mainly be taught using the "lecturing method" in the past. Under this mode, many students feel that the course content is complex, boring, and abstract, only by rote. It is difficult to cultivate students'desire to observe, discover and solve problems. Peer instruction (PI) changed the traditional classroom teaching mode with the mode of students as the subject and teacher as the guider. The results show that the teaching reform of hydraulic engineering geology under PI wins initial success, not only make students to acquire the knowledge, cultivate their learning initiative, but also enhance the level of teachers' teaching research.