High-quality development is an important strategic goal for China’s social development in the 14th Five-Year Plan and beyond. As the Yangtze River Economic Belt is an important link between the east and the west, and connects the north and the south, General Secretary Xi Jinping has held three seminars to plan and orient the development of the Yangtze River Economic Belt. This shows that the government attaches great importance to the role of the Yangtze River Economic Zone as the "main force" in high-quality development and demonstrates China’s determination to build a new model of coordinated regional development. Using the panel data from 110 prefecture-level cities in the Yangtze River Economic Belt spanning from 2011 to 2020, this study seeks to incorporate the digital economy, optimized allocation of capital, labor, and land resources, and high-quality development into a cohesive analytical framework. Additionally, it aims to investigate the influence of the digital economy on the high-quality development. Simultaneously, we empirically analyze the Matthew effect, spillover effect, and threshold effect of the digital economy in facilitating the high-quality development of the Yangtze River Economic Belt using panel uantile, spatial, and threshold models. The findings indicate that the digital economy has a significant positive impact on the high-quality development, and the conclusion has good robustness. The test on mechanism identification reveals that the digital economy can facilitate high-quality development by rectifying the misallocation of capital, labor, and land resources. The test for heterogeneity results indicates that the enabling effect of digital economy on the high-quality development of the downstream area and non-resource-based cities is relatively stronger, and there is a "Matthew effect" of urban highquality development level, that is, the higher the level of urban high-quality development is, the stronger the enabling effect of digital economy is. Further research shows that this influence has spatial spillover effect and threshold effect on urban digital characteristics. As a result, the paper recommends expediting the establishment of digital China, harmonizing competitive regulations and development approaches among urban areas, achieving the unrestricted flow and effective distribution of resources, and providing momentum for the high-quality development of the Yangtze River Economic Belt. Concurrently, it is crucial to establish a support system for the lower reaches of the Yangtze River Economic Belt, enhancing policy preferences and financial backing for resource-dependent cities within the region, refining talent attraction policies, fostering a favorable entrepreneurial climate, drawing in high-caliber professionals for innovation and entrepreneurship, and addressing regional imbalances and disparities in development.