Abstract: Blast resistant door is used for oil and gas, unclear power station and army. The numerical simulation has been done in this paper to study the dynamic response of the blast resistant door under blast loading. The blast resistant class of the door DBD-AD150*240 has been analysed by the simulation. The strain, stress and the deformation of the door under the different blast loading has been studied to to examine whether the door can meet the blast resistant requirement or not to determine the anti-explosion grade of the door. In the present research, a type of sandwich panels was used to absorb the blast energy. The deformation of the energy absorbed structure was studied. Through the numerical simulation study, the anti-explosion grade of the studied antiknock door is determined, and the blast resistant ability of the door was obviously improved when employing the sandwich panels on the blast resistant door.