Power transmission line,especially high-voltage transmission line p lays an important role in electrical power supply system.Therefore,in order to ensure the safety of high-voltage t ransmission line in service,it is of vital importance to detect broken strands and damage faults of high-voltage tra nsmission line timely and accurately.However, the commonly used methods have some problems in practical engineering.Optical t ime domain reflectometry (OTDR) is a commonly used instrument for fiber characterization and fault locati on in optical transmission systems.In this paper,a new method of detecting broken strands and damage faults of high-voltage transmission line based on OTDR technology is put forward.The theory of testing with OTDR is introduced at first.Model experimental study is conducted on a steel tube to simulate the high-voltage transmission wi re, including axial tension test and horizontal shear test.Then damage simulation experiment is carried out on a sec tion of original aluminum transmission wire.The results of the experiment demonstrate that this detecting system can be used to discriminate high-voltage transmission wire broken strands and damage faults accurately and also to estimate the crack width on the wire surface according to the level of the measured optical loss.The proposed monitor ing method based on OTDR shows promising potential in broken strands and damage faults detection of high-volta ge transmission line.