The outage of overhead-lines seriously affects the stability of power system operation, so the establishment of overhead-lines’ failure rate model considering internal and external factors is the key to the risk assessment of power system operation. Based on the failure mechanism of overhead lines, this paper proposes the Multi-Drive-PHM (MDPHM). This model is based on the Proportional Hazard Model (PHM). The model’s baseline hazard function adopts aging failure model and the covariates of connected function include the equipment health status, load rate and weather conditions, and the correlations between these covariates and the failure rate are calculated through the testing statistical hypotheses. The Levenberg-Marquardt method is used to estimate the parameters of this model in the final step. The case study quantitatively shows the impact of different factors on the overhead-line failure rate, verifying the validity of this model. This work is supported by National Natural Science Foundation of China (No. 51537010).