Abstract: The traditional gerotor pump has a constant and low speed, and also the problems of large pressure pulsation and low volumetric efficiency when it is applied to the wide speed operating conditions of the active shock absorption hydraulic suspension system. Therefore, the article from the perspective of the structural parameters of the distribution pair of the gerotor pump, the influence of the tooth-shaped circular unloading groove of the distribution pair on the flow field characteristics under the condition of wide rotational speed were studied. By establishing three-dimensional models of the tooth-shaped circular unloading groove distribution pair with different structural forms, the pressure pulsation and volumetric efficiency of the tooth-shaped circular unloading grooves of different distribution pairs under variable load and speed conditions were studied. The results show that the tooth-shaped circular unloading groove can improve the volumetric efficiency of the gerotor pump and reduce the output pressure pulsation under the condition of high speed when the load conditions are consistent. At the same time, increasing the inlet pressure of gerotor pump can effectively improve volumetric efficiency. When the speed is 5 000 r/min, the volumetric efficiency of the pump without unloading groove is 91.8%, and the volumetric efficiency of the gerotor pump with the unloading groove structure is 92.3%. The output pressure pulsation of gerotor pump with full tooth-shaped circular unloading groove is less than that of gerotor pump without tooth-shaped circular unloading groove. The maximum difference of the pressure pulsation of the gerotor pump corresponding to the toothed circular unloading groove of the two structures is 0.71% in a wide speed range. At constant speed, the larger the load pressure, the smaller the volumetric efficiency of the gerotor pump, and the smaller the pressure pulsation value.