Abstract: Objectiove To study the changes of immune function in liver cancer patients treated with US-guided percutaneous microwave coagulation. Methods The peripheral blood NK cell activities,the level of serum IL-2 and SIL-2R was evaluated,blood samples were obtained before therapy and 1,2,3,4 weeks after therapy. Results The level of NK cell activities and serum IL-2 level were significantly decreased,while the level of serum SIL-2R were significantly increased in liver cancer patients as compared with those in normal individuals(P<0.01).The elevation of NK cell activities(P<0.05),and the decline of SIL-2R level(P<0.01)were observed in patients after microwave therapy Conclusion Microwave therapy can enhance the immune function of liver cancer patients,and play an important role in the antitumor effect.