Abstract:Since the great earthquake in Tangshan City of China dated 1978 , the karst collapses keep increasing because of the damage of rock integration. However , there are many factors to influence karst collapse , including some of prerequisite factors , intensity factors , inducing factors , economic2loss factors and const ruction2resistance factors. These factors compose the risk factors of karst collapse. After determination of the risk value of each fac2 tor , the risk probability per roster is computed for all factors with the method called as fish2bone model. Based on the statistic features of risk probalility of all rosters , the risky areas are plotted in three grades : Highly Risky Area , Moderately Risky Area and Slightly Risky Area. Finally , some suggestions are put forward to avoid or to t reat the risk of collapse.