The geological disaster risk caused by vulnerability of mountain environments is one of the problems that the urban planning for mountainous cities should pay close attention to. This paper takes the comprehensive planning of Shimian County as an example, explores the urban planning strategies for mountainous cities based on geological disaster risk assessment. It proposes systematical planning strategies which take the main thread of the construction of regional ecological security patterns, the adaptive layout of urban system, the disaster prevention for the spatial planning in the central area (site selection, density zoning, and space building for disaster prevention), as well as safety governance of construction land for disaster spots.