Objective:To investigate the effects of RhoA gene silencing by RNA interference on the growth of LoVo colon cancer cells transplanted into nude mice. Methods:The eukaryotic expression vectors of shRNA targeting RhoA were constructed and transfected into LoVo cells. The stable cell colons of RhoA silencing were selected， and the expression of RhoA protein was determined by Western blot. The nude nice were transplanted by subcutaneous inoculation with stably transfected RhoA shRNA plasmid, empty vector and untransfected LoVo cells， respectively. The weight and volumes of tumors were measured 4 weeks after transplantation. The expressions of RhoA, VEGF and MMP-2 in tumor tissue were examined by immunohistochemical staining. Results:The weight and volume of tumor in RhoA shRNA group was significantly lower than that of two control groups (P<0.01). The immunohistochemical results demonstrated that the expressions of RhoA, VEGF and MMP-2 protein were all significantly decreased compared with two control groups (P<0.01). Conclusions:RhoA gene silencing can inhibit the growth of LoVo cell xenograft tumnor in vivo.