A cover body mechanism, installable on a sealed tank body, wherein the cover body mechanism comprises: a first cover body, arranged on the sealed tank body and a second cover body, arranged below the first cover body, wherein a bottom of the first cover body is provided with a groove, the bottom wall of the groove is provided with a first channel opening in a penetration manner, and the first cover body is provided with a second channel opening communicating with the groove; wherein a handle is provided with a connecting end and a holding end connected with the connecting end, wherein the connecting end is movably accommodated in the groove through the second channel opening and connected with the groove through a second rotating shaft, and the holding end is located above the first cover body; and wherein a sealing ring is arranged between the first cover body and the second cover body, wherein the sealing ring is capable of deforming outward and expanding with the rise of the second cover body, so as to be sealingly contact to an inner side wall of a storage cavity in the sealed tank body, characterized in that a connecting base is provided with an annular connecting ring and a connecting arm that is convex on an upper side of the connecting ring, wherein the connecting ring is sleeved with an upper side of the second cover body, an upper end of the connecting arm is movably accommodated in the groove through the first channel opening and is connected with the connecting end through a first rotating shaft, the first rotating shaft and the second rotating shaft are dislocated so that the connecting base and the second cover body rise to a sealed state or fall to an open state with the swing of the handle relative to the first cover body. a first cover body, arranged on the sealed tank body and a second cover body, arranged below the first cover body, wherein a bottom of the first cover body is provided with a groove, the bottom wall of the groove is provided with a first channel opening in a penetration manner, and the first cover body is provided with a second channel opening communicating with the groove; wherein a handle is provided with a connecting end and a holding end connected with the connecting end, wherein the connecting end is movably accommodated in the groove through the second channel opening and connected with the groove through a second rotating shaft, and the holding end is located above the first cover body; and wherein a sealing ring is arranged between the first cover body and the second cover body, wherein the sealing ring is capable of deforming outward and expanding with the rise of the second cover body, so as to be sealingly contact to an inner side wall of a storage cavity in the sealed tank body, characterized in that a connecting base is provided with an annular connecting ring and a connecting arm that is convex on an upper side of the connecting ring, wherein the connecting ring is sleeved with an upper side of the second cover body, an upper end of the connecting arm is movably accommodated in the groove through the first channel opening and is connected with the connecting end through a first rotating shaft, the first rotating shaft and the second rotating shaft are dislocated so that the connecting base and the second cover body rise to a sealed state or fall to an open state with the swing of the handle relative to the first cover body.