Three-dimensional numerical simulations were carried out for a compressor to investigate the stator cavities' influence to the performance and flow field. Detailed analyses of the performance and flow field came to some conclusions: the cavity leakage flow led to decreases in the efficiency

pressure ratio and stall margin of the compressor. The compressor stall margin declines by 5.19% due to the cavity leakage flow. The cavity leakage flow mainly influences the root flow of the stator and rear blades

and changes the compressor stall mechanism. The cavity leakage flow causes flow separation near the hub of the first stator

as a result the second rotor incidence angle increase sharply; consequently the flow separates at the suction side of the second rotor

causing the compressor stall earlier than that without the cavity.