Based on the inter-provincial panel data from 2003 to 2020, using fixed-effects model and dynamic GMM （generalized method of moments)model, the relationship between population aging and carbon emission intensity is analyzed. The role of working-age population, labor productivity, labor quality and labor participation rate in the path between population aging and carbon emission intensity is analyzed by using mediating effect model. The results show that the relationship between population aging and carbon emission intensity is inverted U-shaped.The mediating effect of working age population is not significant, labor productivity and labor quality have partial mediating effects,male labor participation rate and female labor participation rate have masking effects.