With the development of the times, district development, as a kind of large-scale investment project with Chinese characteristics to implement the concept of new urbanization, faces both challenges and opportunities. This paper mainly discusses how planners and designers promote high-quality development in the process of district development. Firstly, the concept, principle and project process of district development are introduced. Secondly, the construction of knowledge system of urban and rural planning is outlined. Finally, on this basis, the paper discusses in detail how planners and designers promote high-quality development in the process of district development from the stages of project decision-making, design and construction preparation for reference.