Abstract: Finite element dynamics models of the cover-U form frame system and the bearing support system are built respectively by using subsystem modeling method.Based on the finite element analysis of the subsystems,the force acted on the bearing support system is obtained and system structural faults appearing in experiment are replayed.By means of the static model,structure of the bearing support is modified,finally an optimum structure form of the bearing support which meets the need of the operation conditions is achieved.Modeling and analysis of the whole cover system show that the strength of the modified cover system is reasonable.In addition,analysis results agree with the testing data very well.