Entering a new stage of development is a great leap in the historical process of the great rejuvenation of the Chinese nation. Entering a new stage of development, implementing new development concepts and building a new development pattern are determined by the theoretical logic, historical logic and realistic logic of China's economic and social development. Entering a new stage of development, we have defined the historical orientation of China's development, implemented new development concepts, defined the guiding principles of China's modernization, constructed a new development pattern, and defined the path choice of China's economic modernization. The new stage of development is a stage of building a socialist modern country in an all-round way and moving towards the goal of the second century. Entering a new stage of development is a great leap in the historical process of the great rejuvenation of the Chinese nation. It is an important decision to build a new development pattern with domestic macro-cycle as the main body and domestic and international dual-cycle promoting each other according to the changes of China's development stage, environment and conditions, especially based on the changes of China's comparative advantages. This is a systematic and deep-seated change that concerns the overall situation, and it is a strategic deployment based on the present and with a long-term perspective.