To reduce the energy consumption and improve the energy utilization efficiency of the hydraulic power source system under the condition of changing loads, it can realize flexible and changeable output flow, pressure and power control. A threephase asynchronous motor was controlled under the variable frequency V/F control mode, a constant pressure pump was driven as a hydraulic power source. It was a high-energy electro-hydraulic power source that realized the compound control of pressure, flow and power.In view of the slow start of frequency conversion,a controllable accumulator was connected in parallel with the main circuit to solve the problem of slow start-up characteristics of an AC asynchronous motor. Firstly, the mathematical models of constant pressure pump, frequency converter and motor were established by using mechanical equations. Secondly, the system simulation model was established by AMESim software on this basis. And a test system platform was built, through the test, the constant pressure characteristic simulation was consistent with the test, confirming that the simulation model was accurate. The pressure and flow characteristics of the power source of the constant pressure pump driven by the variable frequency asynchronous motor were further simulated and tested. The accuracy of the simulation model was verified by comparing the pressure characteristic test with the simulation model. Finally, the simulation model was used to find the parameters of the auxiliary control switch accumulator, and three sets of data were determined for simulation analysis and P-Q and energy consumption tests. The P-Q test showed that the dynamic response time of the pressure controlled by the pilot pressure valve was not more than 0.2s, and the overshoot was not more than 15%;the dynamic characteristics of the flow were poor, and the accumulator was used to assist the start. The time did not exceed 0.2s. The energy consumption test showed that under the condition of high pressure and small flow and non-duty cycle pressure unloading, the motor speed was reduced from 1500r/min to 450r/min, and the motor power was reduced by 70.3% and 64.8%, respectively. The low speed can reduce the energy consumption of the test system by about 3.8kW.