Cask cover of casked drinking water

The utility model discloses a cover of drinking water barrel, which composes a main body of the cover, a central hole of the main body and a small cap outside the central hole. Inside the main body is provided with a sealing gasket. The spot on the sealing gasket where corresponds to the central hole is cut to make an openable slot. The sealing gasket is tongue-shaped in the openable slot. The small cap consists of a top plate and a column connecting component. The outer surface of the column is provided with a protruded ring to matching the main body with the central hole. The cover of the utility model does not need sealing stuff nor does round-pipe-shape fixing seat for the sealing stuff. Thus the inner main body is flat and the disinfectant can reach every corner of the main body. The gap between the main body and the outlet of the barrel is sealed by the sealing slot, and dust or bacilli in the air is prevented to enter the barrel, as a result, the cleanness of the water inside is guaranteed.