Adjustable airtight structure of pneumatic door

The utility model relates to an adjustable airtight structure of a pneumatic door, which is a box body having a containing space. The outside of the box body is correspondingly provided with an opening, the periphery of which is provided with compacting strips. Both sides of the opening are sequentially and outwardly provided with a sliding seat and a pneumatic cylinder, wherein a connecting block is extended from the pneumatic cylinder and is connected with the sliding seat. The connecting block is linked with another connecting block which is correspondingly connected with a box door, and the periphery of the box door is provided with a compacting seat corresponding to the compacting strips of the opening. An adjusting slice capable of adjusting thickness is arranged between the two connecting blocks, and the good sealing effect between the compacting seat of the box door and the compacting strips of the opening can be achieved by adjusting the thickness of the adjusting slice to maintain the constancy of the environment in the box body.