On the basis of the selected model, the maximum likelihood method is used to do the parameter estimation, and K-S method is adopted to conduct goodness of fit test for estimated preferences, reaching characteristic quantities of the device reliability. 根据选择的结果,对分布函数的参数采用最大似然估计法进行了估计,采用K-S的方法对得到的估计参数进行了拟合优度检验,得出了设备可靠性的几个特征量。