Abstract: Objective: To observe the effect of lymphocyte immunization therapy for recurrent spontaneous abortion(RSA). Methods: Fifty-eight cases of unexplained RSA detected with negative blocking antibody were treated with peripheral blood lymphocytes from spouse for active immunotherapy. Results: Forty-nine patients(84.5%) were pregnanted successfully. Three patients were failed(still in treatment),2 cases were lost to follow up after the third treatment,one case was ectopic pregnancy,and 3 cases were aborted(including 1 case of twin pregnancy to six months). Conclusions: Allogeneic immunotherapy on patients with unexplained RSA may be a safe effective treatment,it can furtherly improve the success rate of pregnancy.