Abstract: In order to solve the problem of the secondary accidents in closed fire area, the automatic sealing system of the disaster area is designed with PLC control box, pneumatic control box and closed door. The system makes a judgment on the closed state of closed door by microcomputer system taking single chip microcomputer as CPU core, and sends out instructions to perform the next action, and the closed door is locked by means of pneumatic control system. The results of airtight, explosion-proof and underground field tests show that the device has good air tightness and explosion-proof property, and it can realize the opening and closing of remote automatic control for airtight door successfully, which can effectively guarantee the safety of rescue personnel.