The mechanical parts of the brackets are destroyed in oscillation experimentation, the reasons of destructions were analyzed and researched, the safety factors of the static strength of their supporting parts meet the requirements, which indicates these destructions are fatigue destructions. Based on the fatigue destroying theory and bracket models, from the beginning of the theoretical calculation the fatigue loads were analyzed. Depending on the fatigue destroying theory and the conclusions of the calculation, the correlative designs and technical measures were taken to the main supporting parts. The oscillation experimentation and actual application have proved these technical measures are reasonable and reliable, the problems of the bracket fatigue are solved and the brackets could meet the requirements of the environment.