The inclusive green growth (IGG) model is an important tool to promote the construction of an urban ecological civilization and promote sustainable and green development, but China's related research is still in its infancy. Targeting the problem of cross-regional research on technology set differences, this study proposes a method of combining the super-efficiency slack-based measure model and the Metafrontier Malmquist-Luenberger index to measure the IGG of 108 cities in the Yangtze River Economic Belt (YREB), and analyzes their convergence. Earlier research showed that, under the metafrontier, the upstream cities in the YREB have the highest level of technological efficiency, followed by the downstream and the midstream cities, while the midstream cities of the group frontier have the highest technological efficiency. The main source of China's IGG is technological progress. The YREB has obvious σ-convergence characteristics overall and in the downstream cities, and absolute β-convergence characteristics both overall and in three basins. This research has significance as a reference for the gradual improvement of the IGG of cities in the YREB, and ultimately their overall coordinated development.