This paper focuses on influence of aerocraft actuator on ultimate performance of Hydraulic Load Simulator (HLS). The dynamic response of a HLS is not approximate with different aerocraft actuator which was indicated in experimental phenomenon. That results in an additional workload to adjust the parameters of torque controller. With the help of mathematic description of influence issue, this paper analyzes and presents the principle of this influence in the form of transfer function, which relates to the load stiffness of aerocraft actuator. Simulation results indicate that the proposed principle can be successfully used to explain the influence in accord with the experimental phenomenon.