This study aimed to assess the associations between menstrual characteristics and the prevalence of metabolic syndrome (MetS) and non-alcoholic fatty liver disease. A cross-sectional study was conducted with a sample of 1625 postmenopausal women in China. Subjects were classified into three groups according to the tertiles of some variables related to the reproductive life. We assessed associations in multivariable-adjusted analyses, using logistic regressions. After adjustments for confounding factors, the odds ratios (OR) for predicting the presence of MetS increased gradually: as the years of menstruation increased (18-34 years vs 35-37 years vs 38-46 years: OR [95% confidence interval (CI)] = 1 vs 1.231 [0.942-1.610] vs 1.309 [0.985-1.740], respectively); as age at menopause increased (31-48 years vs 49-51 years vs 52-59 years: OR [95%CI] = 1 vs 1.115 [0.846-1.469] vs 1.315 [0.986-1.753], respectively); and as age at menarche decrease (11-13 years vs 14-15 years vs 16-20 years: OR [95%CI] = 1 vs 0.950 [0.728-1.240] vs 0.862 [0.610-1.119], respectively). Among the components of MetS, the highest tertile of years of menstruation was significantly associated with elevated waist circumference (OR =1.401 [95%CI = 1.092-1.798]), and elevated triglyceride (OR =1.220 [95%CI = 0.934-1.593]). Nevertheless, the association between these reproductive factors and non-alcoholic fatty liver disease was not significant. Longer duration of menstruation and earlier age at menarche were significantly associated with a higher risk of central obesity and MetS in postmenopausal Chinese women.