Aiming at the pump-control differential cylinder system, the strategy of speed and position compound servo control with compensation amount of load force was put forward and the calculation models of controlled variable of speed feed-forward and compensation amount of load force were set up in order to improve the steady state and control accuracy. As for the stable switching between the speed control and position control, the switching parameters, including the difference between actual position and target location, and switching time were studied. The simulation model and the physical-experiment model of this system were set up to make study of simulation and experiment, the results demonstrated that the speed and position compound controlling strategy can be used to realize the control of speed and position of pump control differential cylinder system at the same time, which improved the motion stability of the differential cylinder on the prereguisite of controlling accuracy. Compared with the composite servo control, the system of separate position servo control was also studied in simulation and experiment. The comparing results showed that the composite control strategy mentioned above beared the obvious superiority.