Limited by the harsh downhole working environment and its structural feature, the sliding vane pump (SVP), which is an all-metal artificial lift method considered to be widely used in thermal recovery well and high gas/oil ratio well, has not been widely applied as expected. To further improve the efficiency of SVP, this study explores how to optimize the structure parameters and the usage of the pump based on its lifting characteristics, in view of the stagnation in the development of SVP. The main results show that (a) optimization of the inlet (outlet) position parameters will bring effective pre-expansion (precompression) of each chamber once it enters the closed state, to avoid ineffective suction and high-pressure backflow. (b) The mathematical model of the pressure difference between the two sides of the vane at any position is derived by means of piecewise function. (c) Increasing the number of vanes can not only increase the mean value of instantaneous displacement but also shorten the discharge period and reduce the flow pulsation. Compared with the adjacent even number of vanes, the odd number of vanes has a more uniform instantaneous displacement. (d) A larger cross-sectional area of the rotor groove can result in a lower volume efficiency at the same gas–liquid ratio, and the effect of rotor groove on volume efficiency is more significant under high gas–liquid ratio conditions.