Abstract： Objective To investigate the correlation between female age,menstrual status and the density of breast fibrous glandular tissue. Methods A total of 1 734 subjects with mammography examination were retrospectively analyzed,who were with 28 to 30 d menstrual cycle,or underwent natural menopause for more than 1 years,or with at least one side of the breast had no lesions,from October 2015 to August 2016 in Medical University Of Tianjin Cancer Hospital. At the same time, another 139 cases with mammography examination were treated as nonnatural menopause group, who received hysterectomy or postoperative chemotherapy of breast cancer. The breast fibrous gland tissue density of each subject was automatically calculated by the computer aided diagnosis system. One thousand seven hundred and thirty four subjects were divided into 4 groups according to age,including≤35 years old group(n=217),36 to 45 years old group(n=533),46 to 55 years old group(n=491),≥56 years old group(n=493),and was divided into premenopausal group(n=1 015)and natural postmenopausal group(n=719)according to the menstrual status.The premenopausal group was further divided into four subgroups:menstruation(n=158),one week after menstruation(n=311),two weeks after menstruation(n=316),and one week before menstruation(n=230). According to the status of menopause, the nonnatural postmenopausal group was divided into hysterectomy group(n=62)and drug menopause group(n=77)because of the postoperative chemotherapy of breast cancer. Pearson method was used to evaluate the correlation between age and breast fibrous glandular tissue density.A single factor analysis of variance was used to compare the differences in tissue density of subjects from different age groups and subjects from different menstrual status groups. The independent sample t test was used to compare the difference of the breast fibrous glandular tissue density between the premenopausal group and the natural postmenopausal group and between the nonnatural menopause group and the natural postmenopausal group.Results The tissue density differences of subjects from different age groups were statistically significant, and the tissue density of ≥56 years old group was lower compared to the other groups(P<0.05).A moderately negative correlation was presented between age and breast fibrous glandular tissue density(r=-0.456,P<0.01).The breast fibrous glandular tissue density of the premenopausal group was higher than that of natural postmenopausal group [(20.11 ± 8.54)% vs. (11.30±6.05)%,t=25.138,P<0.05].As to the different menstrual status,there was a significant differences between one week after menstruation subgroup and one week before menstruation subgroup(P<0.05).The density of fibrous glandular tissues in the hysterectomy group and the drug menopause group was(16.27± 6.91)% and(15.44±7.31)%, respectively. There was significant difference between drug postmenopausal group and natural postmenopausal group(t=-5.592, P<0.05). Conclusions Breast fibrous glandular tissue density decreases with the age. The breast fibrous glandular tissue density of the premenopausal women is significantly higher than that of natural postmenopausal women.The breast fibrous glandular tissue density of one week after menstruation is lower than that of the one week before menstruation.