Taking the digital hydraulic cylinder used in the spacecraft transfer platform as the research object, according to its structural characteristics and internal closedloop control principles, the multibody dynamics model was established by using three dimensional (3D) modeling software and ADAMS software. The hydraulic model was established by AMESim software. The software interface integrated the hydraulic model into the ADAMS environment for co-simulation. Based on the simulation model, the positioning accuracy of the digital hydraulic cylinder was researched, and the accuracy of the model was verified by experiments. And according to the simulation and experiment, the method of adjusting the input pulse to improve the accuracy was proposed, which could meet the accuracy requirements of the transfer platform. It is also found through simulation that the fluctuation of the oil supply pressure will cause the piston rod to shake when it is running, and the positioning error is increased.