Carrying out green energy transformation, implementing clean energy power replacement and supply, and developing a new power system are some primary driving forces needed to fulfill China’s carbon-peak and carbon-neutral strategic goals. The construction of new power systems in China’s provinces and cities is developing rapidly, and the lack of a typical model promotes the application. The new power system path design should be based on the actual development of the power grid in different regions, energy use characteristics, and other actual needs to carry out the differentiated path design. In this context, this study analyzes the characteristics of the new domestic power system based on the policy background of the new domestic power system, constructs a new model for power system development stage identification, and proposes the overall design of the new power system development path from the power supply, transmission and distribution, and load sides. It also uses the Hebei South Network as an example to explore the development stage of the Hebei South Grid based on actual development needs. Finally, this study designs a novel power system development path for the entire supply and demand chain for the Hebei South Grid to propose ideas for constructing a new power system in China and to help green energy transformation.