Abstract: Prestressed reinforced concrete (RC) T-beam bridges are more common in highway bridges, the bridge deck damage after the explosion attack is mostly in the form of a breach and affects its ability to pass, but the existing bridge explosion damage assessment studies are mainly concerned about the RC beam bridge piers and columns and the main girder of the post-blast residual bearing capacity, the lack of a more intuitive and rapid judgement of the bridge ability to assess the damage assessment method. In this regard, this paper to pre-stressed RC T-beam bridge deck plate by the explosion load after the breach size as a damage indicator, based on numerical simulation and multivariate nonlinear regression analysis to carry out rapid assessment of bridge deck damage research. The results show that: by comparing the transverse dimensions of the breach in the bridge deck under the action of the explosion, it is found that the influence of concrete strength is relatively small, while the explosion location, deck thickness, spacing of diaphragms, TNT equivalent and proportional blast distance and other parameters have a greater impact; due to the web and diaphragms have a strong enhancement and constraint effect on the bridge deck, under the same conditions, the transverse dimensions of the breach produced by the explosion on top of the deck between the web and the diaphragms are significantly smaller than those directly above the web and the diaphragms. Size is significantly smaller than that produced by the explosion directly above the web, the damage degree of the explosion on the bridge is significantly smaller than that of the explosion under the bridge. Further, based on the above parameters that have a greater impact, it is proposed to use the transverse dimensions of the breach as a damage indicator, the establishment of a rapid damage assessment formula for predicting the capacity of the bridge after the explosion.