<p>Acceleration and deepening of population aging pose substantial challenges to global economic growth. Enhancing total factor productivity (TFP) has emerged as a pivotal strategy to mitigate these challenges and sustain long-term economic development. This paper examines the impact, mechanisms and spatial effects of population aging on TFP using data from 30 Chinese provinces between 2006 and 2019. The results indicate that population aging significantly hinders the improvement of TFP. The primary mechanisms through which population aging hinders TFP growth include constraining factor structure optimization, impeding technological innovation and reducing factor allocation efficiency. This paper also reveals that the negative impact of population aging on TFP is most prominent in the Northern Coastal Economic Zone and the Middle Yangtze River Economic Zone. Moreover, the impact of gradual population aging on TFP is not significant, but when population aging enters an accelerated period, it can have a significant negative impact on TFP. Further analysis shows that population aging does not have significant spatial spillover effects on TFP in neighboring regions, and its negative impact mainly exists within the local regions. In conclusion, the impact of population aging on TFP provides more direct empirical evidence and decision-making references for China to actively respond to population aging and improve TFP from both theoretical and empirical perspectives.</p>