Abstract: To evaluate the effects of four kinds of cadmium salts on C57BL/6 mice implanted with lewis lung carcinoma(LLC), and further investigate the protective mechanism of zinc(Zn). C57BL/6 mice inoculated with LLC were randomly grouped for different drug administration. After 16 days, tumor weight, index of spleen and thymus, and metallothionein (MT) expression were evaluated. CdCl₂ showed significant anti-tumor effects on LLC and could enhance the immune function of mice. The tumor inhibitory rate between CdCl₂(1 mg·kg^-1) and Cd+Zn group showed no significant difference. Compared with CdCl₂(1 mg·kg^-1), MT expression of Cd+Zn group showed a significant increase in liver.In conclusion, CdCl₂ has a significant inhibitory effect on LLC. The most favorable dosage of CdCl₂ is 1 mg·kg^-1. Pretreatment with Zn has protective effects on hepatic cells, and it causes no significant difference about the inhibition effects of CdCl₂ on LLC cells.