ObjectiveTo summarize the relevant studies of pharmacological mechanism of tamoxifen and its influence on ovary function in order to provide information and evidence for the therapy of breast cancer. MethodsPapers published from January 1950 to January 2014, were retrieved in MedLine, OVID, CBM, CNKI databases using the keywords on tamoxifen, drug metabolism, ovary, sex hormone, etc, 1286 papers were retrieved in English literatures, and 621 in Chinese literatures. Criteria of paper adoption:①The clinical and basic studies about metabolism of tamoxifen, metabolic effect of tamoxifen, and gene polymorphism of CYP2D6.②The role played by estrogen receptor and protein cofactors in tamoxifen effect.③The clinical and basic studies about tamoxifen induced ovulation, caused endometrial thickening, changed sex hormone levels. According to the above criteria, 152 papers were selected, and 77 papers out of them were finally analyzed and reviewed. Results①The tamoxifen metabolite 4-OH-N-tamoxifen was the main working component, the decreased levels could predict the poor prognosis.②The CYP2D6 gene polymorphism could affect the metabolic effect of tamoxifen and the therapeutic effect of patients with breast cancer.③The metabolic effect of tamoxifen needed the participation of the estrogen receptors and protein cofactors.④Tamoxifen could affect the reproductive system function through the estrogen receptor of H-P-O axis, ovary, and endometrium. ConclusionsMetabolic effect of tamoxifen is regulated by gene, it could affect reproductive system functions through estrogen receptor. the mechanism that tamoxifen cowld affect the hormone levels and wherther it could reflect the ovarian function by monitering the hormone levels continuously for patients with breast cancer need to be researched.