In response to the crack at the installation side of a certain engine pipeline bracket， the research direction for solving the failure problem was clarified through analysis of the fracture at the bracket crack and the static strength stress of the bracket components. From aspects of part design， processing and assembly， the cause of the problem was determined to be the interaction stress between the bracket and the pipeline， which made the bracket work under original vibration stress and additional stress introduced during assembly. Due to the strong rigidity of the bracket components and weak buffering under stress load， the stress generated from bracket elastic deformation would be transmitted to the hole edge， probably causing the formation of cracks. The improvement with floating structure was designed which has the ability of axial deformation compensation and can significantly reduce the stress transmission. The proposed optimization design is validated by tests.