In order to deeply study the effect of vortex cavitation in the oil suction chamber and its influence on the performance of the circular arc helical gear pump under high speed and high pressure working conditions, the circular arc helical gear pump with sinusoidal transition curve was selected as the research object, the full cavitation model was selected and computational fluid dynamics software PumpLinx was used to simulate the performance of the circular arc helical gear pump in high speed and high pressure conditions, including the position of the vortex cavitation occurrence, formation, evolution and the influence on export flow characteristic. The results show that under high speed and high pressure conditions, vortex flow occurs at the back edge of the oil suction cavity teeth of the gear pump, resulting in vortex cavitation; the cavitation phenomenon at the core of the vortex is the most serious, and then the degree of cavitation gradually decreases towards the edge of the vortex; the vortex cavitation at the location shows a periodic process of formation, development and disappearance; cavitation leads to the increase of flow and pressure pulsation at the pump outlet, and periodic vortex cavitation causes periodic flow fluctuation at the pump outlet, which adversely affect the gear pump outlet flow.