In recent years, the demand for oil has increased year by year. In petroleum engineering, oil transportation is an important process. As an important power equipment for oil transportation in the oil field, the oil rotary pump has the advantages of a wide range of medium viscosity and strong self-absorption, but the fluid flow in the rotary pump cavity is not stable. In order to further improve the performance of the oil rotary pump, numerical simulations by the Fluent software were carried out on oil transfer rotor pumps with 5 meshing clearances and 3 rotor blade numbers. The influence of meshing clearance and rotor blade numbers on the performance of oil transfer rotor pumps was analyzed. The results showed that as the meshing gap increases from 0.1 mm to 0.3 mm, the high-speed flow area in the cavity of the 2-blade oil delivery rotor pump was enlarged, the vortex intensity in the rotor cavity increased, and the smoothness and volumetric efficiency of fluid flow in the pump cavity decreasd. The number of blades increased from 2 blades to 4 blades, the variety of pressure changes in the rotor cavity increased, the fluid flow stability in the rotor pump cavity was improved, and the fluid flow in the 3-leaf rotor pump cavity was the most stable. After the optimized design, the smoothness of the flow in the cavity of the oil transfer rotor pump was improved, and the volumetric efficiency increased by 2.1%, which can better meet the needs of oil transportation in the oil field, and can provide a reference for the further optimization of the oil transfer rotor pump.