Abstract: In view of the fatigue cracking of joint plates caused by vortex-induced vibration of steel tubular members in UHV engineering, the surrounding environment analysis, Vortex frequency identification, vortex-induced force calculation, stress analysis of the solid model of the joint plate and the estimation of the minimum cracking time are carried out. The results show that there is obvious stress concentration at the outermost edge of the stiffening rib in the middle of the joint plate when the member occurring weak axis vibration. The maximum stress amplitude can reach 77.83 Mpa. In theory, the fatigue cracking near the stiffening rib of the cracked joint plate may occur within 4-5 months, which is consistent with the multi-source fatigue cracking indicated by SEM. In order to avoid the occurrence of such events, the following work should be carried out by standardizing the Vortex amplitude control index and developing more flexible vortex characteristic monitoring means.