Abstract: This paper presents a method of calculating the reliable service life of magneto-optic disks by way of analyzing figures of weibull parameters,which overcome the analysis of only one or definite construction of MO disks before. In this method, MO disk is considered as a whole system and the invalid of BER is taken into account. The reliable service life of MO disks is calculated at normal atmosphere by means of analyzing the experiments result which is concluded by acceleration experiments of high temperature.