As a new type of semiconductor lasers, VCSELs have had great influence upon many fields, such as computation, network, sensing, and so on. This papers made some discussions about the performance of VCSELs, applied in optical communication, under high-frequency modulation. A practicable model of its equivalent circuit was brought forward. The authors simulated VCSELs modulating characteristic with PSPICE, the general circuit simulator, and got its characteristic curves at high bit rate by experiment. Those are helpful for optimizing the performance of VCSEL-based data communication networking.