Professional degree Master is a form of postgraduate education in China, which focuses on the cultivation of practical and application abilities. In order to train the practical ability, the case method is introduced into the classroom of the master of control engineering. First the necessity of the case method is analyzed, and explores the basic ideas of case teaching. And then, Taking "smart grid control technology" as an example, the paper explores the production and application of the case. The cases need to simplify the actual project, so as to highlight the relevant knowledge points. Before the teacher guides the students to discuss the case, they are required to explain the background knowledge in advance. Practice has proved that the application of the case method is of great help to improve students' practical ability, understanding and solving practical engineering problems.