Improving the mechanism for implementing the regional coordinated development strategy is an inevitable requirement and key support for promoting regional coordinated development, and an important link in the march towards Chinese-style modernization. By combing the important discussions of General Secretary Xi Jinping on coordinated regional development since the 18th CPC National Congress and summarizing the achievements of China’s coordinated regional development in the past twelve years, the article finds that the CPC Central Committee with Comrade Xi Jinping as the core has followed the objective law to continuously adjust and improve the concepts, mechanisms, and policy systems of regional development, and has made a series of major strategic plans to give full play to the comparative advantages of the regions and to promote the high-quality development of the regional economy. The biggest theoretical achievement is Xi Jinping’s concept of coordinated regional development in the new era, and the biggest practical mark is that China’s coordinated regional development has undergone great changes and made historic achievements. In the new journey, Chinese-style modernization has put forward new requirements and challenges for coordinated regional development. The common prosperity for all is the essential feature of Chinese-style modernization, and regional coordinated development is the inevitable requirement for realizing common prosperity. Improving the strategic mechanism of regional coordinated development should take promoting common prosperity as the core objective. The logic and focus of improving the implementation of the strategic mechanism of regional coordinated development lies in the promotion of the regional economic layout with complementary advantages and high-quality development. Based on the perspective of complementary advantages, coordinated regional development is not only about increasing the total economic volume and optimizing the industrial structure, but also about ensuring that the fruits of development can equitably benefit all people through scientific and reasonable planning and efficient resource allocation, aiming at reasonably distributing the cake. Based on the perspective of high-quality development, regional coordinated development at the macro level goes beyond the single economic growth, but is an all-round change driven by the optimization of economic structure and quality enhancement, aiming at making the cake bigger and better. Cultivating and developing new quality productivity according to local conditions is an important strategy to promote complementary advantages and high-quality development of regional economic layout. On the one hand, the development of new quality productivity not only reflects the further deepening of the region’s original comparative advantages, but also cultivates new comparative advantages for each region. On the other hand, through a new round of technological innovation, the new quality productivity can promote regional development to form new economic growth points and enhance the endogenous growth momentum of the economy. At the same time, the new quality productivity is itself a green productivity, which is an important source of power to enhance the sustainable development of the region.