Abstract: In order to solve the simulation problem of beam pointing in a wide range during the tracking accuracy measurement of photoelectric tracker, a two-dimensional fast steering mirror (FSM) with large aperture and high accuracy was designed. An elliptic and microcrystalline plane mirror was designed with long and short axes of 230 mm and 160 mm respectively, and the surface accuracy was better than λ/30. Driven by the voice coil motors and supported by the flexible support hinges and DSP embedded control system, the swing angle range was ±30 mrad, the motion control accuracy was 5 μrad, the motion control linearity was better than ±0.20%, and the angular resolution was better than 1 μrad. Through the software control, the circular, linear and random motion of the incident beam could be simulated. Finally, the design indicators were tested, which could meet the requirements of tracking accuracy dynamic beam simulation.