Promoting the growth of the Yangtze River Economic Belt is an important strategy for China's overall development. It is of great theoretical value and practical significance to explore how to realize the high-quality economic development of the Yangtze River Economic Belt under the principle of "implementing big protection and prohibiting large-scale development".On the basis of the core-periphery model,and in view of reality of the Yangtze River Economic Belt,the paper establishes a modified multivariate spatial economic model,and makes a spatial mathematical modeling of the 11 provinces and cities belonging to the Yangtze River Economic Belt. Later,the SBM-undesirable empirical model analysis is conducted to further systematically argue the rationality of the segment-development mode and the regional economic integration mode for the Yangtze River Economic Belt high-quality development.The results show that the segment-development mode,due to the obvious influence of administrative barriers,will lead to greater difficulties in the flow of economic factors among regions,which will eventually make the development of the Yangtze River Economic Belt equalized and balanced,not conducive to the high-quality development of the Yangtze River Economic Belt and restrict the regional economic vitality. On the other hand,the regional economic integration mode will continuously weaken the influence of administrative barriers of provinces and cities within the Yangtze River Economic Belt,and improve inner trade conditions. The flow rate of economic factors will also be enhanced among provinces and cities,and ultimately the Yangtze River Economic Belt would effectively change the economic growth mode,form a self-organized agglomeration equilibrium,and achieve high-quality development of the overall economy. Besides,there exists a threshold value for the Yangtze River Economic Belt's agglomeration transformation. The above mentioned regional economic integration mode will lower this threshold value and reduce investment in the transformation process and enhance economic efficiency.