Abstract: Objective :To explore the correlation between the bcl-2 protein expression level or DNA ploidy and the clinical pathology factors in breast cancer patients. Methods : Flow cytometry was used to analyze the bcl-2 expression level and DNA ploidy in cancer tissues, corresponding para-cancer tissues in 63 cases of primary breast cancer patients and 22 cases of benign breast tumor patients. Results : In breast cancer tissues, bcl-2 expression level and DNA index (DI) and s-phase fraction (SPF) and proliferation index(PI) were higher than that in para-cancer tissues and benign breast tumor (P<0.05). DI and SPF and PI in infiltrating non-specific cancer patients was dramatically higher than that in early infiltrating cancer patients and infiltrating specific cancer patients (P<0.05). DI and SPF in lymph node metastasis positive patients were higher than that in lymph node metastasis negative patients. The bcl-2 protein expression had no correlations with age, pathology type, tumor size, lymph node metastasis and clinical stage (P>0.05). The bcl-2 protein expression had negative correlation with SPF and PI (P<0.05). Conclusion : The bcl-2 protein expression and DNA content play an important role in tumor genesis and progression of breast cancer patients. Both DI and SPF have correlations with lymph node metastasis. DNA content can be the important target in predicting the prognosis of breast cancer patients.