Objective  To investigate the spatiotemporal variations in sexual size dimorphism among Chinese Han students.  Methods  Based on the eight students’physical and healthy investigations, the data on the stature and body mass were systematically collected for 343 928 and 344 029 Chinese Han students aged 19 to 22 years from 1985 to 2019, respectively. The sexual stature dimorphism index (SSDI) and sexual body mass dimorphism index (SBMDI) were employed to analyze the distribution in different periods and regions. In addition, we focused the relationships between these two indices and the per capita consumption expenditure. Results  Positive secular trends were observed in the SSDI and SBWDI among Chinese Han students throughout the 1985 to 2019 period. Notable similarities were identified in the SSDI and SBWDI between northern and southern students. Compared with the SSDI, the SBWDI exhibited significant disparities between urban and rural areas, and demonstrated a positive association with the per capita consumption expenditure.  Conclusion  The female buffering hypothesis possesses a limited range of spatiotemporal adaptability, and the trait more susceptible to environmental influences is better suited to test this hypothesis.