In order to make analysis and design of the parameters of laser resonators easily,laser resonator software arithmetic is studied and realized using computer.ABCD matrix mechanism is used to analyze and design laser resonators.To obtain the generic and universal method,which is used to program,the matrix of all elements is considered as complex matrix.And,beam quality factor M2 and the index of the media are also considered.When the imaginary parts of the complex matrix are zero,and the beam quality factor M2 and media index equal to one,the stated method will be transformed to the usual conditions which are fundamental mode transmitting through real elements in the air.Based on the method of multi-mode transmitting through complex elements in the media,laser resonator software,which can analyze and design stable standing cavity,stable travelling cavity,unstable standing cavity,unstable travelling cavity,phase conjugate cavity and beam transmission,is realized by VB programmed language.