Abstract: Scanning electron microscope and energy dispersive spectroscopy methods were used to investigate the inclusions of 55SiCr spring steel produced by WISCO,Baosteel and Nippon Steel. The result shows that aluminum deoxidization smelting process is used to obtain high level of cleanliness for Nippon Steel's spring steel. For Baosteel and WISCO's spring steel,non-aluminum deoxidization smelting process is used,but the control of the inclusion's plastic deformation capacity still needs to be improved. And then,the 55SiCr spring steel samples of smelting process were analyzed to study the evolution of inclusions' composition. Based on the results of thermodynamic calculation,a suggestion for the 55SiCr spring steel inclusion's plasticization was proposed,theOshould be controlled from 0.0009% to 0.0020%,and theAl controlled from 0.0002% to 0.0008%.