The invention discloses an adjustable double-cover pressing type pressure vessel which comprises a tank body, a tank cover, a height adjustable mobile bracket and an adjustable pressing device. The tank cover is mounted on the tank body. The adjustable pressing device is mounted on the mobile bracket. An upper ring mounting plate and a lower ring mounting plate are arranged at the connection part between the tank cover and the tank body. A hydraulic opening is formed in the tank cover. A detachable hydraulic cover is arranged on the hydraulic opening. The pressing device is mounted on the mobile bracket, and the mobile bracket can drive the pressing device to move, and therefore, the pressing device is not limited to one pressure vessel, and can be moved to press another pressure vessels; and the positions of arc-shaped pressing plates are adjusted through the mobile bracket, so that the pressing positions of the arc-shaped pressing plates are more accurate.