This article analyzed the leading role of urbanization to commercial housing market capacity. The research showed：（1）In recent ten years，new urban population have made commercial housing market capacity increased by 80 millions square meters，it was the half capacity of the market；（2）the prospect of commercial housing market capacity will be optimistic in Guizhou，the market capacity will increase by 220 million square meters because of demand of new urban population and improved housing demand of original residents.