Abstract: Airplane was assembled by thousands of components.The joining components were the most important parts to transfer load and fix other compents. The failure of these components would badly influence the security of airplane. This paper discussed failure of structure joining the vertical empennage and fuselage on the airplane. The failure form was crack and fastener non-fixing.Fault-tree was used to analyse the crack failure primarily; correlative structures were simulated with CAE(computer aided engineer) software that analyzed stress and vibration of structure and then the effect of vibration of structure was discussed from structure desigining, stiffness matching, and forced assembly.The results show that the cracks of joining structure were mainly caused by airflow orifice on the fuselage; the airflow orifice disorganized air along the course of airplane.In addition,the vibration of engine promoted the initiation and propagation of the cracks.According to the analysis results, re-designing structure shape and improving processing manner were implanted to improve the anti-fatigue strength, local stiffened structure was used to reduce vibration . Corresponding correcting steps were validated by flight presently.