China has been undergoing with rapid urbanization, which is a transformative process that could  set off a new wave of economic growth. In this process, demograpdhic change in mountain regions has much effect in line with constructing towns and cities. This paper investigates mainly four issues: 1) Is the mountain population structure still young? 2) What is  the major reason for mountain population decline and rapid aging? 3) How does mountain people structure look like? And 4) What are the crucial points in making balanced development among land use, industrial transition and social services? We aim to explore the drivers of change, to project the possible trend, and to recall the policy makers to pay attention on mountain population issue, in order for a balanced development. Data base is from two sources: population cnesus and sattistics Chongqing, and GIS data and land maps of Chongqing. In the analysis we combine two methods that are based on cohort demography  analysis, and spatial distribut via GIS model at village scale.