Abstract: In order to explore the influence on the single screw pump leakage of different structure parameters, a geometric model of 1/2-line all-metal single screw pump was constructed as an example. Based on PumpLinx software for the transient numerical simulation, the reliability of results based on CFD model was verified by the hydraulic characteristic test. And the flow variation law and flow field distribution of single screw pump with different total helix angles were studied. The results show that under the condition of constant unit helix angle, the time-average flow rate increases with the increase of the total helix angle and the unit pressure difference decreases. The minimum instantaneous flow rate decreases with the increase of the total helix angle. The value is basically consistent and close to the theoretical flow rate of 17.90 m~3/h. The pressure on both sides of the oblique leakage gap changes with the engagement position of the stator and rotor, and the pressure difference at a specific position decreases with the increase of total helix angle. The maximum value of the transient leakage velocity at the monitoring point of a specific meshing zone decreases with the increase of total helix angle. Relevant research results have certain reference significance for leakage analysis and optimization design of single screw pump.