Aiming at the phenomenon that the thrust bearing of the turbocharger was damaged at high rotational speed, the turbocharger was researched to analyze the variation of the axial force with the different working conditions. The models of turbocharger compressor and turbine, including wheel gap and seal ring clearance, were constructed. Then ANSYS-ICEM was used to mesh grid and ANSYS-CFX was used simulate the flow field of turbocharger compressor and turbine with the different working conditions. The results show that the axial force of turbocharger increases with the rotating speed increasing and the deviation from the theoretical value increases. Keeping the rotating speed constant, the effect on axial force of seal ring clearance is not obviously but the leakage is low with the tight seal ring clearance; the axial force will decrease with the flow increases.