Abstract: Recently the collisions between over-high trucks and bridge superstructures have become a serious threaten to the safety of city traffic. In order to reduce the loss due to collision accidents, it’s critical to precisely calculate the collision loads. This work firstly simulates the collision process between over-high trucks and bridge superstructures based on high precision finite element model, with primary influencing factors that control the collision loads being discussed. Then by ignoring the minor influencing factors, a simplified model for the collision between over-high trucks and bridge superstructures has been developed. The time-history results of simplified model agree well with those of the high precision finite element model, thus the proposed simplified model can be used in practical application.