Chinese modernization coincides with the acceleration of population ageing, and therefore faces a scientific choice regarding economic development paths and promotion methods. In the context of an ageing population, the elderly care industry will continue to develop, thereby promoting economic growth. Based on China's provincial panel data spanning from 2013 to 2022, this paper analyzes the impact and mechanism of population ageing and the development of the elderly care industry on economic growth. The results show that the deepening of population ageing inhibits economic growth, whereas the development of the elderly care industry promotes economic growth. Mechanism analysis indicates that the development of the elderly care industry plays a crucial regulatory role in the relationship between population ageing and economic growth, which will significantly weaken the negative impact of population ageing on economic growth. Heterogeneity analysis shows that there are significant differences in the relationships among population ageing, development of the elderly care industry, and economic growth in different regions, and the linkage effect between population ageing and the development of the elderly care industry only plays a significant role in regulating economic growth in the western region. It is imperative to promote innovation and development within the elderly care industry, strengthen regional coordinated development, optimize the social security system, implement refined policy management, and achieve coordinated development among population ageing, the elderly care industry, and economic growth.