Karst collapse in intermontane basin is not completely different from that in Tangshan City.The karst collapse occurred mostly in the period between lower water and high water and it happened in loose cover of different thicknesses.In the region, water table in loose cover is the same as that in bedrock.On the basis of the characteristics, the main causes of karst collapse are analyzed in terms of the formation mecha- nism of soil cavit y.It is found that over pumped groundwater induces karst collapse in thick cover while rain- water seepage induces karst collapse in thin cover.The measures for preventing collapse are proposed accord- ing to the distribution of the disaster.