The invention relates to a self-falling sealed cabin door structure and a mounting method. The self-falling sealed cabin door structure adopts a mechanical sealed structure, has good sealing property,is opened stably, and has high application value on design of sealed cabins and special equipment. The self-falling sealed cabin door structure comprises a sealed door mechanism, a door opening mechanism and a control system; the sealed door mechanism comprises a fixed door frame and a movable door plate; the door opening mechanism consists of a locking mechanism and a door breaking mechanism; the locking mechanism comprises a mounting base plate, racks, a gear, rack limit blocks, a transmission shaft and a drive motor; the door breaking mechanism comprises a mounting base, a connection rod mechanism and an electric cylinder; the control system comprises a monitoring camera, a control unit and a base station; a control module controls the drive motor and the electric cylinder to be powered on; the drive motor drives the gear through the transmission shaft, the gear drives the racks to move, the racks stretch into the rack limit blocks, and the movable door plate is closed; the electric cylinder pushes the movable door plate through a second connection rod, so that the movable door plate is opened.