The plasticity map of 304HC stainless steel was determined by using tensile and compressive test. The effect of Cu on the hot plasticity of 304HC stainless steel was analyzed. The microstruc- ture, inclusion and fracture surface were studied by using the method of optical microscopy, SEM, EDS and EPMA. The results showed that Cu has effect on the hot plasticity and the hot plastici- ty of 304HC stainless steel decrease with the increase of Cu content. The deformation temperature also has much effect on the hot plasticity, the suitable deformation temperature are 1100-1200°C. The reason is that the. brittle compounds were precipitated from austenite during cooling. These brittle compounds are CusS, Cu2O and PbCl etc. The plasticity map of 304HC stainless steel was determined by using tensile and compressive test. The effect of Cu on the hot plasticity of 304HC stainless steel was analyzed. The microstruc- ture, inclusion and fracture surface were studied by using the method of optical microscopy, SEM, EDS and EPMA. The results showed that Cu has effect on the hot plasticity and the hot plastici- ty of 304HC stainless steel decrease with the increase of Cu content. The deformation temperature also has much effect on the hot plasticity, the suitable deformation temperature is 1100-1200 ° C. The reason is that the. brittle compounds were precipitated from austenite during cooling. These brittle compounds are CusS, Cu2O and PbCl etc.