Abstract: Two kinds of antibacterial stainless steels were prepared by adding copper into martensitic and austenitic stainless steels respectively,then solid solution and aging treatment were performed.The microstructure of the two steels was analyzed,and the antibacterial properties were investigated using the cover membrane method.The results show that the austenitic antibacterial stainless steel had better antibacterial properties than the martensitic antibacterial stainless steel,because smaller and more dispersive ε-Cu phase were precipitated in the former than in the latter.Martensitic and austenitic antibacterial stainless steels were easy to kill bacillus coli and staphylococcus aureus.Salmonella typhi deratting needed a certain period of time(>4 h).Killing candida albicans took a long time(>8 h).With the prolongation of antibacterial action time,the sterilization function of antibacterial stainless steels increased remarkably.