Abstract: Objective To investigate the T cell subsets changes of patients with malignant tumors treated by Cryosurgery.Methods 109 tumors were collected from 105 patients who have been diagnosed as pathological stage Ⅲ or Ⅳ period advanced cancer and the expected survival time of patients were more than three months since June 2005 to December 2006.Samples were collected one week before and after 1-2 weeks treatment with Cryosurgery.T-cell subsets of peripheral blood CD3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺were analyzed using flow cytometry without other treatment.Results After 3-12 months of Cryosurgery treatments the tumor was getting reduced significantly on CT and tumor was found disappered in some patients's.It was also found that the peripheral blood CD3⁺, CD4⁺, CD4⁺/CD8⁺from malignant tumors patients treated with Cryosurgery were significant increased(P＜0.05)compared to that of before treatment.Conclusion Treatment of Cryosurgery can enhance the cellular immune functions and improve the anti-tumor capacity of patients with malignant tumors.