Purpose <p>This study aims to investigate the trends in sperm concentration among fertile Chinese males over the past four decades, addressing whether there has been a change in sperm concentration and identifying potential causes.</p> Methods <p>The research included 94 Chinese and English literature sources, covering 27 provinces and cities across China, encompassing a total of 14,634 individuals. A least squares linear regression model was applied to analyze sperm concentration data.</p> Results <p>The analysis indicated a significant downward trend overall from 1984 to 2023 (<i>P</i> = 8.42<i>e</i> − 10). A single-factor analysis of variance was performed, categorized by the year of sample collection, showing a decline in sperm concentration across each decade of the collection years (<i>P</i> = 1.01e − 08), with the most significant decline noted between 2004 and 2013 (<i>P</i> = 0.0035).</p> Conclusion <p>The findings suggest a general decline in sperm concentration among fertile Chinese males over the past forty years, with a more pronounced decline after the twenty-first century, potentially associated with escalating environmental pollution due to heavy industrialization, poor lifestyle habits, and radiation from electronic devices. Further research is essential to elucidate the causes of and broader implications associated with this downward trend.</p>