The test rig of the power mechanism of the direct drive volume control winch type heave compensation system was established，and the working principle of the A10VG closed variable pump was introduced. By using AMESim software to establish the simulation model of the variable pump and the power mechanism test bed，by simulated and analyzed the operation and control currentdisplacement characteristics of the displacement control mechanism of the variable pump，the simulation and experiment research of the static characteristics，dynamic characteristics and commutation characteristics of the power mechanism were carried out. The simulation model and parameter setting of the power mechanism of the direct drive volume control winch type heave compensation system are basically accurate，but still need to be further optimized and perfected. Simulation and experimental results lay the foundation for the followup study of the winch heave compensation system.