Aiming at the speed control of hydrostatic transmission system, a design method of adaptive fuzzy sliding mode control with friction torque dynamic compensation is proposed. The friction torque dynamic compensation method is introduced to e nhance the response of the system. The adaptive fuzzy controller is introduced t o solve the problem of the uncertain parameters and external disturbances of the system, so that the design of controller can be performed without accurate model . The adaptive law derived by Lyapunov method can guarantee the stability of con trol system and reduce the high frequency chattering. Simulation results show t hat the control approach can decrease the tracking error, enhance the system’s rob ustness and attenuate the high frequency chattering in the control signal. 