Pump efficiency is an important indicator to reflect the utilization ratio and management level of pumping outfit. A reasonable theoretical model of pump efficiency is of great significance to improve lifting efficiency and optimize structure parameters of sliding vane pump. On the basis of the mechanical structure and working principle of SVP, the analytic model of volumetric efficiency is established from the perspective of leakage and degree of fullness respectively. The analytic model of mechanical efficiency for SVP is established considering viscous friction and contact friction. Based on the theoretical model, the influence of structural parameters (inlet/outlet opening angle,rotor-groove radius, vane number) of SVP on pump efficiency was analyzed. The research shows that the pump efficiency increases with the increase of opening angle, and with the increase of displacement, the difference of pump efficiency decreases.Meanwhile, the pump efficiency will increase with the rotor-groove radius and vane number decrease, so on the premise of meeting the requirements of pump weight and sand control, the rotor-groove radius and vane number should be as smaller as possible.