Abstract: In order to study the dynamic response of reinforced concrete slab under blast loading, the method of dimension analysis was employed to obtain the relation between spherical charge's quality, distance between explosive and target plate, and the deflection of reinforced concrete target plate. A three-dimensional numerical model for air-explosive-reinforced concrete slab was developed by using the finite element software AUTODYN. Considering the fluid-solid coupling interaction among explosives, air, and components, the simulated results were consistent with the experimental results. The fixed conditions were changed from two-side to four-side. The distance between target and explosive and the charge weight were respectively controlled to investigate their effects on target deformation. The results showed that the central deflection of reinforced concrete slab increased linearly with the increase of charge quality when the scale distance was larger than 0.6m/kg^1/3 (not consider the near-field explosion and contact explosion). However, the central deflection exponentially decreased with the increasing distance between explosive and target if the distance between explosive and target is alterable.