Abstract: In this paper, the eigenvalue problems of multilayer dielectric waveguide consisting of arbitrary number of layers are solved by microwave network method. A general program with the function of computer graphics has been made for analyzing the dispersion characteristics and the electromagnetic field distribution of N layer dielectic waveguide. As an example of practical applications, the procedure of mode conversion and separation in delectric branching waveguide is vividly demostrated through analyzing the field distribution of asymmetric dielectic structure and the general rules of mode conversion are discussed.