由于构造和安装等原因，换热器、蒸汽发生器的换热管支承间通常存在间隙。而各种随机因素（如加工误差等）的影响，使非有效支承的出现是不确定的，因此必须用概率的方法来讨论这一问题。文章在比较讨论临界流速概率分析的基础上，修正、补充了支承失效概率估计的表达方式；提出了一种实用的流体弹性不稳定性的概率分析方法。 Due to the construction and installation and other reasons, there is usually a gap between the heat exchanger tubes of the heat exchanger and the steam generator. However, due to the influence of various random factors (such as machining errors, etc.), the emergence of non-effective support is uncertain. Therefore, we must discuss this issue in a probabilistic way. Based on the comparative analysis of the critical flow rate probability analysis, the article amended and supplemented the expression of the estimation of the probability of bearing failure, and proposed a practical probabilistic analysis method of fluid elasticity instability.