Lots of key parts of rail vehicles are connected by screw thread fastening. Therefore, it is very important to evaluate the service performance of bolt correctly and efficiently. Through the evaluation of the service performance of bolts, a series of engineering application problems of bolt connection can be well solved. In this paper, model building, theory checking, simulation analysis and bench test verification are studied in a unified way, so as to get the theory and research method of engineering application. According to the bench fatigue test, the 10.9 grade bolt was fractured after loading about 3 million times, so the bolt could not meet the life cycle requirement under this working condition.