Obiective To evaluate the value of DNA ploidy patterns and proliferous activity in tumors diagnosis.Methods Total 32 cases of human breast neoplasms were examined by Flow Cytometry (FCM) to get the parameters of DNA index (DI),proliferating Index(PI),S-phase fraction and ploidy patterns.Results The results showed that acuoploidy rate of breast cancer cases was 70%.However,there were no multiploidy patterns appeared in benign breast tumors.DI,PI and S-phase fraction of breast cancer was higher than benign breast neoplasms.DI of Ⅲ grade breast cancer was higher than Ⅱ grade.Conclusion Aeuploid and high proliferous activity could be used for identification of benign and malignant breast diseases.