A pumping unit with incomplete gear and rack reversal was designed for smooth motion and low energy consumption. This paper first describes the working principle of the pumping unit. The kinematical equation of the pumping unit is established on the basis of analyzing the kinematic relationship between the first tooth meshing area, the normal meshing area and the final tooth meshing area of incomplete gear and rack. The kinematic relationship curve of the pumping unit is obtained by ADAMS simulation. The simulation results show that the theoretical model is correct. By comparing the results with the conventional pumping unit, it can be seen that: the pumping unit has a smooth movement of the up-down strokes, with fluctuations of movement only in the process of changing directions. The incomplete gear and rack drive is smooth, which can improve the kinestate of the pumping unit.