A method of establishing a damnification self-diagnosis system for carbon fiber enhancement resin base composite material is characterized in that the steps includes: (1) measuring the front and the rear electrical resistances of different type composite materials with epigene actions of stretching, impacting and bending by a electrical resistance measuring instrument, building a stress-electrical resistance database of the composite material, determining the damnification of the composite material by using a ultrasound scanning method, and determining the corresponding relation of damnification-electrical resistance variation; (2) analyzing and processing the composite material electrical resistance variation by a computer, diagnosing whether the composite material having damnification or not real time, and generating automatically a abridged general view of the composite material status. The advantage of the invention is that by means of using the conductivity characteristics of the composite material, the composite material is taken as an inductive element for its mechanics and electrology performance, so as to self-diagnosing the damnification of the composite material. The system has the characteristics of real time monitoring, accurate diagnosis, and the system is visual and intelligible.