In the background of comprehensive new urbanization promotion,how to realize the benign symbiotic development of multiple regional space in China,especially how to speed up the urbanization level in wester n underdeveloped a reas is a major problem of Ch ina’s urba n ization. Ta k ing Shuicheng County for example, the paper analyzes urbanization problems in western underdeveloped mountainous areas:seriously lagged urbanization, low-level equilibrium urban spatial distribution,low industrial structure and urgently ecological resource crisis. It points out three traits constraining county urbanization in wester n underdeveloped mountainous a reas: underdeveloped macro-economic backdrop, severe mountainous landform, and minority living social background. And based on traits constraints, it critically absorbs successful urbanization exper iences. At last,it const r ucts a dyna m ic mecha n ism model of u rba n ization in Shuicheng County,and put forward three urbanization driving mechanisms:government policy,industrial economy and the subject position of peasants,in hope of providing a reference for healthy and stable urbanization in western underdeveloped mountainous areas.