An experimental system was established for the performance test of the developed prototype of electric motor pump. The parameters consisting of the electric power input, hydraulic power output, rotor speed and internal pressure in the electric motor pump were measured. The characteristic of the rotor speed, noise, power and efficiency changing with the outlet pressure of the prototype was obtained. Compared with the traditional hydraulic power unit which has the same power as the prototype, the volume of the prototype was reduced by 50%, the dimension in axial direction shortened 61% and the noise level lowered 7dB, and the speed of rotor in the prototype decreased apparently with the increased of the output pressure. Furthermore, the bubble separation as a result of the narrow channels and the extra leakage due to the ineffectual seal in the prototype were discussed, and the corresponding solutions were proposed. 