Abstract: Taking GA250-8.5 air compressor as an example,an air compressor screw rotor lightweight optimization design method is proposed.First of all,the basic situation of the air compressor is briefly introduced,and the lightweight design of the screw rotor is carried out respectively,and then,based on this,the deformation strength and support position of the lightweight screw rotor are simulated and analyzed by means of finite element simulation analysis,so as to further improve the optimization effect of the screw rotor of the air compressor to ensure that the performance of the screw rotor is kept good while, reduce the weight of the screw rotor,so that it can play a greater role in the air compressor.