采用数理统计方法对大庆油田常用的三种钻井泵活塞的寿命分布规律作了研究，应用可靠性理论计算和分析了活塞可靠性指标。同时，为比较和综合评价三种活塞的质量，对活塞寿命方差和均值的差异性作了检验。为探求活塞寿命与各影响因素之间的关系，对清水介质条件下新旧两种标准活塞强化试验数据进行了多项式拟合和分析。研究表明，三种活塞的使用寿命均服从二参数威布尔分布，活塞的失效类型属耗损型。因此，延长活塞寿命的关键是延长活塞的正常磨损阶段。必须从改进设计，提高制造水平和改善使用条件等方面综合提高活塞的耐磨性。 The law of life distribution of three drilling pump pistons commonly used in Daqing oilfield is studied by using mathematical statistics method. The reliability index of the piston is calculated and analyzed by the reliability theory. At the same time, to compare and comprehensively evaluate the quality of the three pistons, the variances of piston life variance and mean were tested. In order to explore the relationship between piston life and various influencing factors, polynomial fitting and analysis were conducted on the data of the two standard piston intensification tests under the condition of fresh water medium. The research shows that the service life of the three kinds of pistons obeys the two parameter Weibull distribution, and the failure type of the piston belongs to the wear type. Therefore, the key to prolong the life of the piston is to extend the normal wear stage of the piston. The wear resistance of the piston must be comprehensively improved from the aspects of improving the design, improving the manufacturing level and improving the service conditions.