To explore the influence of the boundary layer suction on the aerodynamic performance and flow field structure of the transonic compressor, the stator blade of transonic compressor was taken as the study object, the suction slot of the compressor suction surface was studied by using the numerical simulation method.By comparing the prototype cascade with the suction schemes, it can be found that the suction on the surface suction has obvious effect to restrain the upper corner separation, and at the same time of reducing the loss,the diffusion capacity is slightly improved.When the suction slot is near the core of the separation vortex, the suppression of the corner separation is the best, and the total pressure loss of the cascade is reduced by 16.68 %. Using imported  guide vanes instead of moving vanes  to create near stall conditions can get rid of the disadvantageous  factors such as  high cost of whole stage test bench and danger under bad conditions in subsequent experimental research.