Population aging is a challenge for China at present, and it can have an important impact on the upgrading of industrial structure. Based on the provincial panel data of 11 provinces and cities in the Yangtze River Economic Belt from 2009 to 2019, the relationship between population aging, technological innovation and industrial structure upgrading is analyzed. The results show that the aging of the population can have a positive impact on the upgrading of the industrial structure. When technological innovation is used as the threshold variable, the relationship between population aging and industrial structure upgrading presents a single threshold feature. After the threshold value is crossed, the positive effect of population aging becomes stronger.