The invention discloses a pressure vessel with double cover bodies. The pressure vessel comprises a tank body and a tank cover arranged on the tank body, wherein an upper mounting plate and a lower mounting plate are separately arranged at connecting parts between the tank body and the tank cover and are fastened together through arranged hoop bands; hydraulic openings are formed in the tank cover; and a detachable hydraulic cover is arranged on each hydraulic opening. According to the pressure vessel disclosed by the invention, the tank cover and the tank body are arranged by clamping through the hoop bands; hoop grooves of the hoop bands can wrap and clamp the upper and lower mounting plates therein; one end parts of the hoop bands only need to be connected, so that one ends of the hoop bands only need to be opened when the tank body is opened; transverse grooves and transverse luges are separately arranged on the side walls of the upper and lower mounting plates and in the hoop grooves; and the transverse grooves and the transverse luges are matched for use, and are mutually pressed, so that the fastness of the tank cover and the tank body is improved, and the sealing property is also enhanced.