Abstract: An experimental investigation on the effect of the rotor wake on unsteady loading of downstream stator has been carried out in a low speed single stage axial compressor.The unsteady pressure distribution along the stator blade was measured,and the effects of axial gap between rotor and stator,operating rotation speed and mass flow of the compressor were investigated in detail.The experimental results show that all these factors have a great effect on the rotor-stator interaction.The incidence change caused by the velocity defect in the rotor wake has a major impact on the unsteady pressure distribution and lift of the stator blade.The amplitude of the pressure fluctuation reaches maximum at the blade leading edge and decays rapidly towards the trailing edge on the pressure side.The interaction intensifies with the decrease in the mass flow or the increase in the rotation speed.The results of the investigation on the influence of axial gap between rotor and stator (l) show that,the unsteady pressure distribution and the lift of the stator blade fluctuate strongly as l<0 4,and the fluctuation intensity decreases quickly as lincreasses.