Abstract: In this paper,the interaction between tip leakage flow and passage secondary flow in a compressor stator was investigated by numerical method.The calculations are based on the 3D Navier-Stokes equations expressed with nonorthogonal curvilinear coordinates and corresponding nonorthogonal velocity components, and the explicit time marching algorithm and Baldwin-Lomax turbulence model are adopted.An efficient integral H-grid is employed to solve the grid singularity in the tip region.The details of generation and development of passage vortex,leakage vortex and tip separation vortex were predicted.The computed results show,because the direction of the leakage flow is opposite to that of the passage secondary flow,proper leakage flow can weaken the intensity of passage vortex and improve the flow in tip region.