Based on three-dimensional Euler equation, a model of a certain three -stages compressor is established and calculated by adopting a method of body force. This paper mainly analyzes the effect of inlet guide vanes (IGV) on inlet distortion and the relation between IGV's angle and total pressure distortion in operation at the designed rotating speed. The result shows that IGV can improve the flow field and reduce the distortion parameter. The distortion range and the intensity are respectively reduced by 21.4% and 10.2% at the three stage rotor entrance. IGV has a favorable ability of rectification and anti-distortion. With the rise of IGV's angle, the distortion intensity gets lower, but it will come to increase while the IGV's angle reaches a certain value. Meanwhile, IGV will do the best with 45° .