Abstract： Objective To evaluate the immunological effect in the tumor loaded rats with treatment of heat-shocked antigen-pulsed dentriric cell(DC vaccine)and radiofrequency ablation(RFA).Methods The heat-shocked freeze-thrawed walker 256 cells were used as antigen to stimulate the bone-marrow derived DCs of the rats.Fourty-eight SD rats subcutaneously loaded with walker 256 tumors were randomly divided into four groups:control one(n=10)was treated with RFA only,control two(n=10)was treated with DC vaccine only,control three(n=10)was treated with RFA and un-pulsed DCs,and experimental group(n=18)was treated with RFA and DC vaccine.The CIM+T lymphoeyte、CD8+T lymphocyte and CD+/CD8+ratio in peripheral blood of the rats were detected before treatment and four days after treatment.The sizes of the tumors before and after treatment were measured on ultrasonography.The survival period of the rats were recorded.Results After treatment,the CD4+T lymphocytes and the CD+/CD8+ratio were significantly increased,and the CD8+T lymphocytes were significantly decreased in the experimental group than those in the controls(P＜0.05).At the same time,the experimental group had smaller sizes of the tumors and longer survival period than those of the control groups(P＜0.05).Conclusion Used after RFA,DC vaccine stimulated with heat-shock and freezethrawed antigen can effectively enhanced the immunological response of the rats,which results in slow growth of the tumors and long survival duration of the rats.