In order to study the internal flow field characteristics of the non-circular planetary gear motor,the geometric model and finite element model of the non-circular planetary gear motor were established,and the simulation parameters of the model were set and the grid independence was verified.The flow field of a non-circular planetary gear motor was simulated and the velocity variation rule of the flow field at the oil film position was investigated.The flow rate and volumetric efficiency of Q100,Q160 and Q250 non-circular planetary gear motors under inlet pressure from 5 MPa to 20 MPa were studied.The flow rate and volumetric efficiency of Q250 non-circular planetary gear motor with oil film gap of 0.02 mm,0.03 mm and 0.04 mm were studied.Finally,the accuracy of the simulation model was verified by prototype test.The results show that under the same inlet pressure,the larger the volume is,the higher the volumetric efficiency is,and the volumetric efficiency decreases with the increase of oil film gap.When the oil film gap is 0.02 mm and the pressure is 5 MPa,the motor volumetric efficiency can reach 90.9%.The curves of volumetric efficiency and torque relationship obtained by experiment and theory are basically the same,and the maximum error is only 5.76%,which verifies the accuracy of the simulation model.