Abstract: Under different experiment periods and environments，the same equipment showsdifferent reliability.As the environment condition changes，the equipment reliability becomes a function of the environment，which is called a reliability curve.Given the estimation of the reliability curve，one can predict the equipment reliability for unknown environment. The log-normal data is discussed，the estimator is provided， the strong consistency is proved and simulation is used to show the estimator can be used in practice.

Key words: reliability, log-normal, environment

摘要： 同型号设备的可靠性根据不同的使用环境发生变化。随着环境指标的不断恶化或改善,可靠性形成环境的函数称为可靠性曲线。估计出这条曲线后,就可以对未知环境下的设备可靠性给出合理的预测。在不同的试验阶段，可靠性曲线的形状一般有显著的不同。作者利用全体试验数据估计最后试验阶段的可靠性曲线，对于对数正态总体研究不同试验阶段的可靠性曲线的估计问题,给出了估计方法，证明了估计量的一致强相合性,并用计算机模拟试验说明方法的可用性。

关键词: 可靠性, 对数正态分布, 环境