This study used the coordinated development of the regional economy and ecological environment in the Yellow River basin as the research object and selected 13 indicators representing the regional economic subsystem that reflect economic scale, economic structure, and economic efficiency in order to explore a path of high-quality economic development suitable for China’s national conditions and realize the modernization of China with common prosperity for all people. The coupling weights of each indicator were then calculated separately, along with the degree of orderliness between the two subsystems of the regional economy and ecological environment. Finally, the degree of synergy between the two subsystems was calculated. The subjective weights and objective weights of each indicator were first estimated using hierarchical analysis (AHP) and conflicting correlation among criteria (CRITIC). The findings reveal a strong growth tendency in the regional economic development of the Yellow River basin and a wave-like growth pattern in ecological environment indicators. Since it overtook the ecological economy in 2017, the orderliness of the regional economic subsystem has continued this growth trend, demonstrating that the regional economy is in front of the ecological environment and is in a dominant position. The Yellow River basin’s composite system of regional economic and natural environment exhibits a low-level synergy stage and an M-shaped development pattern of alternating increases and decreases. As a result, many solutions are suggested, including promoting high-quality growth with greater levels of opening, modifying the regional economic structure, and stepping up ecological environmental protection.