Investment and financing mechanism is an important measure for urban development. However，with the transformation of land finance and economic development，the development and upgradation of cities to metropolitan areas is facing sustainable dilemma and funding gap. Combining with planning theory，this paper innovatively puts forward investment and financing development planning initiatives to achieve the goal of high-quality urban development. This paper mainly adopts the methods of literature review and experience induction to construct a special planning framework for investment and financing in metropolitan areas，which includes three working modes，two planning paths and one set of supporting working mechanism. Finally，according to the practice of the framework，this paper puts forward corresponding policy suggestions，which have reference value for the development of urbanization and the governance of big cities.