【Abstract】 Objective To investigate whether the phenanthroline complex SODm of copper salicylic acid inhibit the tumor effect of three negative breast cancer cell line MDAMB231 bearing nude mice in vivo or not.Methods The breast cancer model of nude mice with MDAMB231 cancer cell line was built. SODm and DMSO were injected by intraperitoneal injection in the treatment group and control group, respectively. The doses were 100μl with 7 times, once every other day. The tumor volume and weight of those nude mice are observed and recorded after administration. Results It was found that the method of tumor tissue fragments inserting wass better with faster tumorigenicity and higher tumor rates. The MDAMB231 tumorbearing nude mice model was constructed by this method. It was proved that the nude mouse model was constructed successfully by seeing irregular mitosis in HE staining. We choose the concentration of 05μg/μl of SODm, namely 50μg in every time, because of the better effect and high security. The tumor group growth curve in the treatment group was significantly lower than in the control group. But the weight fluctuation was no significantly different in the two groups.Conclusion The breast cancer cell line MDAMB231 tumorbearing nude mice model is constructed by the method of tumor tissue fragments inserting. SODm can inhibit the tumor growth of breast cancer cell line MDAMB231 tumorbearing nude mice model in vivo.