Abstract: The distributions of PRL (prolactin),NADHDH (NADH dehydrogerose), GDH (glutamicdehydrogenase) and LDH (Lactate dehydrogenase) activity in breast lesions and their relationshipsin breast cancer were studied by histochemical methods. The PRL positive rate in breast cancer andbenign lesions was 80.5% and 85.7% respectively; the highly enzyme activity rate of NADHDH,GDH and LDH in breast cancer was 73. 2%, 39% and 82. 9% respectively, and in benign lesionswas 51.4%,51. 4% and 65. 7% respectively, the activity of NADHDH and LDH had siguifical increasing in breast cancer. Close correlations were found among the PRL POsitive rate or semiquanative grades and the NADHDH, LDH activity, and close correlations also were found among theGDH, LDH activity and the NADHDH activity. These results suggested: A large of breast cancersmight be dependence of PRL;The NADHDH, GDH and LDH activity might be good enzyme biological marker of breast cancer and might have important significances in predicting prognostic value and choosing scheme of therapy of breast cancer.