Abstract: The cable dome proposed by Geiger based on Fuller’s idea of tensegrity is a new type of space structures. Studies on the initial prestress distribution and mechanical behavior of domes subject to static and dynamic loads have been carried out. However the structural behavior of the dome after one or some cables become slack or ruptured is little involved. Taking Geiger domes and Levy domes as examples, the failure mode of these two types of domes subject to different load cases are investigated and their behavior are compared. Some conclusions are finally drawn which will guide the further research and application of cable domes.