Abstract: Turbocharger is an important power component of special power equipment. Better sealing is the key factor to ensure the normal operation of the turbocharger. Uneven pressure caused by high speed operation of the impeller is usually an important cause of leakage. Based on the fluid mechanics analysis method, a finite element model was established. The internal flow field analysis and flow characteristics of a centrifugal pump seal structure were studied. The variations of compressor leakage and internal pressure at different speeds and narrow outlet negative pressure were discussed. The sealing performance of the seal structure was verified. The results show that the sealing structure has a good effect of preventing oil leakage at the compressor end due to high-speed centrifugal effect, and leakage occurs at high speed. The research results provide reference for improving the sealing structure of vortex booster.