The whole set of excavator was composed of hydraulic，mechanic and control systems. Simulation model of each system was built through using MATLAB software, and then the whole set of excavator model was gotten through connecting different systems and simulated. Finally the motion trajectory was obtained for the manipulators. The influences on system performance by changing parameters of hydraulic and mechanic systems could be studied through analyzing each system according to the simulation result. The hydraulic and mechanic systems were built by SimHydraulics and Second Generation SimMechanics tool-box respectively, and accurate simulation results were obtained by setting the parameters of simulation model based on the actual characteristics of hydraulic elements and measurements of manipulators. This virtual simulation can implement an integrative technique of mechanics electronics and hydraulics simulation, which can provide references for optimizing design of different systems of excavator, at the same time, provide a new method to studying each system of the excavator.