As a place of human settlement and the creation of human civilization, City is a concentration area of population, constructions, productions, wealth (both material and spiritual mental) and disasters well.Disasters of same magnitude occur in cities may result in much larger losses than that occurred in rural and remote areas.Tangshan earthquake in 1976, as a typical under-city earthquake, has caused huge losses.China is now in the period of rapid urbanization and economic growth.Existing cities are expanding almost in directions and becoming denser, meanwhile many new towns are under construction in current China.In recent years several disasters occurred and bring us severe damage.Lots of towns, newly built up during past few years were destroyed during Wenchuan earthquake in 2008, the federal town destroyed by Yushu earthquake and the hardest-hit area of Zhouqu attacked by debris flow this year also are rapid-developed towns in northwest China.The main reasons of those severe disasters can be concluded as: underestimate of potential disaster risk, lag of disaster prevention & mitigation countermeasures, serious deterioration of ecological environment.The rapid Urbanization and economic growth and social transformation provide both opportunities and challenges for disaster prevention & mitigation.Hence the current period is a critical period for disaster prevention & mitigation in China.In the process of economic-social development and transformation, the pattern and characteristics of disasters and their causal factors will change as well.Accordingly, the size, feature and disaster resistant ability of disaster-bearing-body are changing.Therefore, to well handle the relationship between urbanization and disaster prevention & mitigation is undoubtedly a great task for ensuring economy-societys stable, healthy and sustainable development.In China, many severe earthquakes occurred in areas of low-fortification intensity, almost one third landslide and debris flows occurred in beyondconcern areas.The occurrences of these disasters expose that Chinese cities ability of preventing disaster is far from that of desired.This paper points out that the key reasons for current situation can be attributed to following factors such as underestimation of potential disaster risk, lag of prevention and mitigation planning, insufficient disaster prevent investment and lack of powerful disaster management system and countermeasures.To reduce the disaster-caused losses and change the current adverse system and mechanism of disaster prevention & mitigation, and based on the problems we are facing and the lessons learned form international experience, this paper propose a set of proposals to meet the urgent needs of disaster prevention & mitigation and the requirements of building up low-carbon city and society during the acceleration period of urbanization and economic transformation in China.