In order to study the strain performance of optical fiber composite overhead ground wire(OPGW) in long-term operation, Brillouin optical time domain analysis(BOTDA) is used to monitor the strain of new cables and old cables in different icing environments, and the Brillouin frequency of fiber in OPGW cables in long-term external environment is compared and analyzed. The test results show that the operation time and icing level are the main factors affecting the strain performance of fiber in OPGW cables.