Abstract: Objective:To improve the diagnosis rate of malignant tumor by detecting exfoliated cells,and validate the application value of exfoliated cells.Method:Sputum and pleural effusion and ascites slides were made,using Wright-Giemsa staining,and observed under a microscope to check whether have atypia cells or malignant tumor cells.Result:The 34 patients with malignant tumor patients in our study included 19 cases of serosal metastatic carcinoma,with 14 positive case which positive rate was 73.68%. The other 15 patients had primary lung cancer,with 11 positive cases which positive rate was 73.33%.Conclusion:The exfoliated cells detection might have very good application value in the diagnosis of malignant tumor.