使用概率法计算了配气凸轮的挺柱运动精度，从理论上剖析了影响挺柱运动精度的因素，比较了两种型线的工艺敏感性，从对加工偶然误差的概率分析出发为评判凸轮型线的加工性提供了一个新判据。 Probabilistic method was used to calculate the precision of the cam with tappet. The factors affecting the precision of the tappet were analyzed theoretically. The process sensitivity of the two types of profiles was compared. From the probability analysis of the accidental errors, The machinability of the profile provides a new criterion.