A new method for analyzing the debonding problem of a single prestressed anchor is proposed based on the catastrophe theory. A simplified nonlinear shear slip model of the anchorage interface is proposed. The total potential energy of the anchorage system is obtained using the elastic theory based on the assumption that the anchor is an elastic body. The catastrophe theory is introduced to simplify the energy function of anchor to the normal form of cusp catastrophe model. A failure criterion of anchor is established and the debonding analysis is conducted. The results show that the softening behavior of the anchorage interface can be reasonably described by the established nonlinear shear slip model. The distribution of the shear stress between the rod body and the surrounding grout gradually evolves into a single peak curve with the increasing drawing load

and the whole anchorage interface softens until damages occur at the ultimate state. The proposed theoretical formula for critical loose displacement is simple and practical and may provide theoretical tools for analyzing the debonding of a single prestressed anchor. Finally

the rationality and feasibility of the method proposed is also examined through an engineering project.