Abstract: With panel data from 30 provinces in China from 2000 to 2022, this paper empirically analyzes the transmission mechanism of economic disparities and their convergence in the eight major comprehensive economic regions. The results show that in the process of developing a national unified market, total factor productivity largely determines regional economic disparities, while capital output ratio and human capital explain the remaining smaller parts. Marketization improves total factor productivity through three transmission mechanisms: technological innovation, human capital flow, and industrial transformation and upgrading, thereby promoting regional economic growth. Improving the level of marketization in various regions and the mediating effect of enhancing total factor productivity are not only conducive to promoting regional economic growth, but also increase the speed of regional economic convergence, thereby promoting rapid convergence of regional economic growth. It is suggested that the marketization level in various regions should be improved; technological innovation, human capital flow, and industrial transformation and upgrading, and narrow the gap in total factor productivity between regions should be promoted; and a mechanism for balanced and coordinated development of regional economy to promote the coordinated and balanced development of the economy in all regions of the country should be established.