Abstract: Objective To detect the changes of T lymphocytes CD3⁺,CD4⁺ and CD8⁺ blocking efficiency after initiate immunotherapy,monitor the effect of immunotherapy and explore the immunological occurrence mechanism of RSA. Methods A total of 82 patients with three times or more than 3 times unexplained recurrent spontaneous abortion patients were selected.Flow cytometry was used to measure T lymphocytes CD3⁺,CD4⁺ and CD8⁺ blocking efficiency of these 82 patients,Wilcoxon rank sum test were used to analyze the difference between two groups,Chi-square test was used to analyze the relationship between positive changing of T lymphocytes blocking efficiency and the result of pregnancy. Results The level of CD3⁺,CD8⁺ T lymphocytes blocking efficiency was significantly increased in peripheral blood of unexplained recurrent abortion patients after initiate immunotherapy (Z=-2.147,-2.622,P<0.05),CD3⁺ T lymphocytes blocking efficiency before active immunotherapy were 0.31(-0.51 to 1.09),CD3⁺ T lymphocytes blocking efficiency after active immunotherapy were 1.02(0.09 to 2.33);CD8⁺ T lymphocytes blocking efficiency before active immunotherapy were 0.47(-0.53 to 1.83),CD8⁺ T lymphocytes blocking efficiency after active immunotherapy were 1.39(0.55-2.88),while there is no significantly differences in CD4⁺ although blocking efficiency were slightly unregulated (Z=-0.552,P>0.05),CD4⁺ T lymphocytes blocking efficiency before active immunotherapy were-0.04(-1.40 to 1.30),CD4⁺ T lymphocytes blocking efficiency after active immunotherapy were 0.52(-1.10 to 1.35).After active immunotherapy,the pregnancy rate of positive blocking efficiency is 42.9%.he pregnancy rate of negative blocking efficiency is 19.4%.The pregnancy rate was higher in the RSA patients with positive blocking efficiency than the patients with negative blocking efficiency (P<0.05). Conclusion After active immunotherapy,T lymphocytes blocking efficiency of peripheral blood recurrent spontaneous abortion patients were unregulated,T lymphocytes blocking efficiency increasing after active immunotherapy in recurrent abortion patients may be helpful to maintain pregnancy.