Based on the characteristics of system of highly hydraulicmechanical coupled of the excavator working equipment assembly, a hydraulicmechanical integrated simulation method was proposed. By applying the technology of computer integrated simulation and optimization, the models of mechanical system and hydraulic system were built separately, and cosimulation of the hydraulic system and mechanical system was realized. The dynamic performance of the working equipment was analyzed, and modeling and simulation efficiency were improved. The accuracy and reliability of the cosimulation is verified by comparing the followed up signals with the control ones of system.