Abstract: With the development of mechanical structure to the direction of lightweight, the flexibility of the member gradually increases, thus the dynamic analysis method taking the member as a conventional rigid body is no longer applicable. Appropriately increasing the relevant experiment of the modal analysis mechanical in the teaching process of the mechanical dynamic, combining vibration mode theory of dynamics machinery with experiment operation, to solve the intrinsic mode of the actual object to be application and validation of related theories, modal theory allows students more in-depth understanding which is very innovative. This paper first introduces the theoretical basis of the complex modal analysis by cantilever test to help the students have a deeper understanding of the modal parameters which have the real physical meaning. Then the writer tries to introduce the experimental analysis of the process to the research activities to improve the quality of teaching, enhance the quality of students, and achieve the purpose of scientific exploration. With reasonable modeling and analyzing, also credible results, this paper has good application value.