Trichinella spiralis has restrain effect on tumors. Different amount of T. spiralis can emerge different tumor inhibition effect T. spiralis infection can reduce tumor growth to various extents in mice bearing tumor cells at different times post infection. Each developmental stage of T. spiralis in the host may have anti-tumor effect T. spiralis may play anti-tumor roles by stimulating cell-mediated immune response, and/or possessing tumor-associated antigen and anti-tumor active substances of the parasite.