Abstract: A sealing structure includes a bottle and a cap sealing the opening of the bottle. The bottle includes a body, an opening formed on the body and a flange protruding from periphery of the opening. The flange has a curved shape having a lower end depressed and connected to periphery of the body to form a neck portion. The cap includes a skirt portion which surrounds the periphery of the body and has a plurality of teeth equally spaced on periphery of the skirt portion and extending longitudinally along the body and a plurality of radial protrusions protruding toward the periphery of the body between every two adjacent teeth. The teeth are pressed by a machine in a lower position thereon so that the radial protrusions abut periphery of the neck portion, and the cap abuts the flange and is conformal with and completely fitted to the flange.