Abstract: In order to improve working efficiency and service time of double helix single screw pump,the effects of its structure parameters on working efficiency and service time were studied.Based on double parameter Mooney-Rivlin model,a three-dimensional meshing model taking material nonlinearity,internal pressure and inertia effect of the rotor on the rubber lining into account,was established for the double helix single screw pump.The effects of interference fit and eccentricity change on the stator rubber lining’s stress and fatigue failure were acquired from the analysis.Simulation results showed that frictional torque increased from 88.52 N·m to 466.51 N·m and stator lining stress increased from 1.4 MPa to 1.8 MPa,when interference fit increased from 0.2 mm to 0.6 mm under eccentricity 7.5 mm.Frictional torque increased only from 240.00 N·m to 264.77 N·m,when eccentricity increased from 7.3 mm to 7.5 mm under interference fit 0.4 mm,however,the peak stress on stator lining increased from 1.28 MPa to 1.62 MPa.This showed that the rational combination of interference fit and eccentricity could increase work efficiency and service time of the screw pump.The work in this paper established a theory foundation for the design and structure parameter optimization of the double helix single screw pump.