Aiming at the problem of low accuracy and sensitivity of outer strand breakage monitoring of optical cable, a high-precision monitoring method of outer strand breakage of optical cable based on optical fiber temperature sensing is designed. The high-speed data acquisition circuit, signal amplification and photoelectric conversion circuit of optical fiber temperature sensor are analyzed to obtain the optimal monitoring mode. The optical fiber temperature sensor is arranged on the optical cable to collect the outer strand breaking temperature data. Wavelet de-noising method is introduced to construct the signal model of optical cable outer temperature data, separate the effective signal and noise, and realize the high-precision monitoring of optical cable strand breakage. Taking 24B1-45 and 24B1-08 Optical Fiber Composite Overhead Ground Wire (OPGW) optical cables as examples, the experimental results show that the signal-to-noise ratio of optical fiber temperature sensor can reach 152 and 157 dB, and the response frequency can reach 6 230 and 6 310 times/s. After the application of this method, it can ensure that it is not subject to too much interference with high monitoring accuracy, and meet the requirements of high-precision monitoring. Therefore, it can effectively detect the broken strand of the outer layer of the optical cable through the temperature, which provide a reliable guarantee for the fault monitoring of the outer layer of the optical cable in remote areas.