Hydraulic impactor is one of hydraulic equipments used commonly in the engineering construction. Due to the high acceleration of the moving components and the properties of the inertia working oil pressure during the working process, it’s quite different compared with the working condition of the conventional hydraulic equipment. It’s necessary to establish computer simulation model rapidly and accurately during the study of the hydraulic impactor. The hydraulic impactor simulation system based on the theory of power bond in AMESIM system which takes into account including the main functions and characteristics of hydraulic impactor can realize the calculation of main simulation parameters of the impactor quickly. From the simulation of the design parameters the impactor of the existing YYG250 hydraulic excavator, we find that the error between the simulation results and test results is within 5%. It proves that the simulation model is correct and reliable. It provides a good platform for the study of the parameters design and shock properties for different series impactor.