During the process of reliability evaluation in electric power communication network, the main problem lies in quantization and calculation of the reliability of optical fiber cables. In order to solve the problem, a probabilistic distribution model is established in this paper, which is applicable to failure rate analysis of optical fiber cables in electric power communication network, based on existing three-parameter Weibull distribution. By consulting the relevant National and Electric Power Industry Standards and the characteristic indexes given by the main cable manufacturers, three new influence parameters are proposed as deformation parameter, structure parameter and time parameter. Limitations of existing data can be improved by using an algorithm that consulting traditional golden section method and an approximate method for parameters fitting of maximum likelihood estimation, then value ranges of these parameters are calculated. This model can reflect influence of different factors on the reliability of optical fiber cable. Experimental results have proved that this model is practical.