Based on an optical transmission model with nonlinear self-focusing (self-defocusing) effects, a (2+1)-dimensional nonlinear Schrdinger equation is obtained under nondimensionalization. The (2+1)-dimensional variable coefficient nonlinear Schrdinger equation is transformed into the standard (2+1)-dimensional nonlinear Schrdinger equation by using similarity transformation. Interactions between two optical vortex solitons, among four, five and six optical vortex solitons in the waveguides are discussed with different vortex-core spacing and initial phase difference, respectively, by numerical simulation. Some new conclusions are obtained through analyzing the above results. 1) The shape of vortex soliton with selfsimilar charcteristics sustain during the propagation along z-axis. 2) Multiple vortex solitons interact with each other during the propagation along z-axis especially when the distance within them is smaller than a definite value, meanwhile the energy flow among them. Some are strengthened, and some are weakened.