In order to improve the response velocity and reduce the energy consumption of the electro-hydraulic power source, a new type of electro-hydraulic power source composed of variable speed driving constant pressure pump was designed. According to different working conditions, the constant pressure pump was driven by frequency converter driving three-phase AC motor and servo motor respectively. Through the principle of electro-hydraulic power source, dynamic response theoretical analysis and experimental verification, it is showen that the dynamic response of frequency converter driving AC motor is poor, and the dynamic response time of servo motor driving is not more than 0.1 s.The energy consumption of the two variable speed drives was further analyzed. The test shows that the energy efficiency of the two electro-hydraulic power sources increases with the increase of load pressure and speed; when the load pressure reaches 20 MPa and the speed increases to 1 500 r/min, the energy efficiency of the hydraulic system driven by variable frequency asynchronous motor is 0.74 and that of the hydraulic system driven by servo motor is 0.8.