Abstract: Aiming at the problems of defects suchas corrosion and fracture of prestressed anchor cables under long-term operation, a theoretical method to determine the defect location of anchor cables is proposed based on the strain monitoring technology and the numerical simulation tests on the middle, left and right defective anchor cables. The experimental results show that there is a relationship between the defect location and the strain, and the results and trends of the numerical simulation and physical tests are basically the same. The relationship between the cable strain and the defect location is established through 15 groups of numerical simulation tests on different defect locations. It provides a feasible way to determine the defect location of cables and also a technical support for long-term safe operation of prestressed anchorage engineering.