Cities have offered diversified ecosystem services for human wellbeing, while various kinds of problems emerging in urban development have hindered the sustainability of urban ecosystems. This paper presented the major challenges for urbanization including ecological and social problems as a result of rapid urban development. Based on the connotation of sustainable development, theory of Social-Economic-Natural Complex Ecosystem and Driver-Pressure-State-Impact-Response (DPSIR) model, urban water supply and sewage treatment systems, urban waste emission reduction, urban transportation and regional planning, food systems in response to urban expansion, and urban clean energy systems were systematically discussed to achieve the urban transformation. In view of the urban sustainable development in China, it is not just about city itself but also about its integrated relationships with its surrounding regions. Therefore, the paper suggested that the coupling and coordination mechanisms between urbanization and regional ecology be studied and established based on the five "transformations".