The invention discloses an automatic sealing mechanism integrating the unfolding, folding and glue sealing functions. The automatic sealing mechanism comprises a machine frame, a conveying device used for conveying boxes is arranged on the machine frame, a box pushing mechanism is arranged opposite to the box entry end of the conveying device, a frame body used for containing original boxes is installed on one side of the box pushing mechanism, a box unfolding mechanism opposite to the larger side surfaces of the boxes is arranged on the side opposite to the side, provided with the frame body, of the box pushing mechanism, the movement direction of the box pushing mechanism is perpendicular to the movement direction of the box unfolding mechanism, and a lower box folding mechanism is arranged right below the box pushing mechanism and the box unfolding mechanism; an adjustable suspension bracket is arranged on the side surface of the conveying device and is sequentially provided with an upper box cover folding mechanism and a glue sealing mechanism in the conveying direction of the boxes.