To investigate the age-related nomograms and change trends of reproductive hormones, and prevalence of androgen deficiency (AD) in middle-aged and aging men from 2 studies. Two cross-sectional studies were conducted at 5-year intervals in Chinese community-dwelling men living in the same area. A total of 434 (Study 1, S1) and 944 (Study 2, S2) men aged 40 to 69 years were recruited as subjects and 59 (S1) and 98 (S2) men aged 20 to 39 years as controls to measure serum reproductive hormone levels. Serum total testosterone (TT) levels did not change significantly in S1, whereas TT levels increased in S2 with aging. Serum calculated free testosterone (cFT) levels gradually decreased with aging; however, only men aged 40 to 69 years showed this trend in S2. Serum luteinizing hormone (LH) and sex hormone binding globulin (SHBG) levels gradually increased, and serum testosterone secretion index (TSI) and free testosterone index (FTI) levels gradually decreased with male aging. The mean annual decrease values of serum cFT were 2.705 pmol/l in S1 and 1.060 pmol/l in S2. The cut-off values for AD in S1 and S2 were 9.13 nmol/l and 9.35 nmol/l for TT, and 169.00 pmol/l and 213.90 pmol/l for cFT. Using TT or cFT cut-off values, mean AD prevalence was 14.52% or 44.70% in S1, and 6.36% or 16.53% in S2. Based on cFT cut-off values, prevalence of AD increased gradually with male aging in a range of 25.30% to 61.63% in S1 and 1.20% to 23.03% in S2. The change patterns of serum LH, SHBG, TSI and FTI levels in middle-aged and aging males were consistent; however, there were differences in serum TT and cFT change patterns in S1 and S2 with male aging. cFT cut-off values were the optimal metric to evaluate AD, which can be present a ladder-like change in prevalence of different age groups.