A synthetic jet generator was used as an active control method to control the flow in an annular compressor cascade.It was found that the total pressure loss of the cascade could be reduced effectively.2D Particle Image Velocimetry(PIV) was used to measure the flow field around the blades.Flow fields were acquired under different incidences

jet frequencies and intensities.It was found that synthetic jet had huge impact on the flow field.With proper jet frequency and intensity

flow separation on the blade suction surface was suppressed evidently

and the blade wake intensity and width were reduced.Streamlines around the blade were smoother.These changes were consistent with the decrease of total pressure loss.The mechanism of this active control method was analyzed.