本文介绍随机应力的测试和数据处理方法．以客车车身骨架作为例子，讨论了概率密度函数、自相关函数和功率谱密度函数，并利用这些函数来分析和讨论客车的动力特性，骨架的疲劳损伤和疲劳寿命． This article describes random stress testing and data processing methods. Taking passenger car body skeleton as an example, the probability density function, autocorrelation function and power spectral density function are discussed. The functions of the bus are analyzed and discussed with the dynamic characteristics of the passenger car, the fatigue damage and the fatigue life of the skeleton.