Precast concrete composite (PCC) slabs are widely applied in prefabricated construction due to their advantages of rapid construction, quality control, durability and cost-effectiveness. Terrorist incidents and accidental explosions have increased abruptly, causing huge economic losses and casualties. As the main load-bearing members of structures, the slabs are prone to damage due to larger load surface under blast loading. To examine the dynamic behaviours of the PCC slab, the field blast test under different explosion distances was firstly conducted. The incident and reflected overpressures-time histories, as well as the damage patterns and displacement-time histories of PCC slabs were measured. Then, the explicit dynamic finite element (FE) program LS-DYNA was employed. The reliability of the FE analysis approach was verified by reproducing the responses of PCC slabs. Furthermore, the influence parameters, i.e., strength of concrete of cast-in-place and precast layers, rebar yield strength, interface position, as well as thickness on the blast-resistant performance of the PCC slabs were further discussed. The compressive strength of the concrete and interface position have negligible influence on the dynamic response of PCC slab, while increasing the rebar yield strength and slab thickness can significantly reduce the maximum and residual deflection. Thus, an appropriate increase of slab thickness in structural design can significantly improve the blasting resistance of structures.