Height limit protection frame of railway bridges apply to the road crossing the railway bridge, its role is to ensure the safety of the railway bridge to prevent road motor vehicles to hit the bridge beam, causing beam damage and even endangering the safety of the railway lines. Therefore, it is necessary to do in-depth discussion of collision mechanism and failure mode of height limit protection frame of railway bridges under the impact of the over-high vehicle, in order to improve the survivability of protection frame to protect the safety of the railway bridge and rail transport. Some rules and characteristics were obtained by establishing collision model of height limit protection frame of railway bridges and the over-high vehicles using the software of ANSYS/LS-DYNA and studying the dynamic response of protection frame impact loading by the vehicle under the different parameters. Thus for the similar protection frame structure design, maintenance and damage assessment provide theoretical support.