Abstract: The current situation of electrical and mechanical professional courses is analyzed in this paper.Especially for the exsisting traditional teaching of the mechatronics system design,the disadvantages of arranging teaching contents according to disciplines and sub-chapters are put forward.Put forward the new teaching mode of applying case-based teaching to the teaching of specialized courses.Through the construction of several typical cases in the design and teaching of mechatronic system,the content of each subject module is organically integrated into the case.In the case,the knowledge structure is penetrated so that the teaching system becomes systematic and complete.At the same time,the cases are closely linked with engineering practice.Practice shows that the new teaching mode arouses students' interest in active learning,enables students to master the overall design of mechatronic system,and cultivates and enhances students' abilities to solve practical engineering problems.