Abstract: The cold deformation characteristics of 316L stainless steel were investigated by compression testing with different deformations. The true stress-strain model and work-hardening model were obtained by fitting the test data with a modified Ludwik model. It is found that the modified Ludwik model can formulate the relationship between stress and strain of the stainless steel. The flow stress of the stainless steel during cold deformation is divided into three stages:the high work-hardening stage, the stable work-hardening stage, and the low work-hardening stage corresponding to the deformation less than 0.02, between 0.02 and 0.29, and greater than 0.29, respectively. Electron microscopy results indicate that the work-hardening mechanism and microstructure characteristics of the stainless steel are different in the three stages.