The experiment of Mach-Zehnder interference is expanded to realize the experiment of three-beam and four-beam interference. By changing the parameters of beam vector angles，beam intensity and polarization states，the interference light fields of one-dimensional periodic fringes，one-dimensional modulation fringes，two-dimensional periodic optical lattice and two-dimensional modulation optical lattice are obtained. By providing the interference simulation module of light，students can simulate the multi -beam interference by themselves，and this makes the students deeply understand the interference theory. Through the content expansion of the light interference experiment by combining the experiment and the virtual simulation，it not only enriches the teaching content of the interference experiment，improves the students interest，but also helps to expand the students professional knowledge and to understand the research content in related fields.