Abstract: Research on the dynamic discrepancy of the integral type and multi-section crossrail,jointed by the high-strength bolt is required.This paper focuses on the dynamic characteristics of the three-section bolted crossrail.The dynamic experiment of the crossrail is carried out at three installation conditions,such as free-free condition,fixed on machine tool,and working condition.At the same condition,the integral crossrail,which ignore the bolted joint,is modeled by three-dimensional software and analyzed by the finite element method(FEM).By comparing the experiment and analysis results,the influences of the bolted joints on three-session beam are explored and no signification discrepancy of the integral and three-section crossrail is found in dynamic characteristics.Therefore,the bolted joints have slight influence on the three-section crossrail,and the conclusion provides an experimental basis for the design,analysis and optimization of the three-section crossrail.