To study the repairing effect of NADH on PC12 cells damaged by chemical drugs, we determined the cytotoxicity of chemical drugs (cisplatin, doxorubicin and rotenone) on PC12 cells with cell proliferation test and MTT assay. At the same time, we analyzed the cyclin protein, GTPase binding protein and transglutaminase Ⅱ content with flow cytometry(FCM). NADH significantly inhibited the cytotoxicity of chemical drugs on PC12 cells. Cisplatin,doxorubicin and rotenone upregulated the expression of cyclin D1 and down regulated the expression of cyclin A and B1 in PC12 cells. On the contrary, NADH increased the expression of cyclin A and cyclin B1 and decreased the expression of cyclin D1. NADH could upregulate the expression of GTPase binding protein and transglutaminase Ⅱ, which were decreased by chemical drugs in PC12 cells. It is suggested that NADH could inhibit the cytotoxicity of chemical drugs to PC12 cells, which are associated with the regulation of cyclin proteins, GTPase binding proteins and transglutaminase Ⅱ.