A sealing structure capable of withstanding water pressure, which has a zipper on two sides of a flexible member at an opening of a container, one margin of the opening is a vertical extension of a buffer plate. Fitted to one end of the buffer plate is a pillar-shaped inside fastener unit. Another margin of the opening is a vertical extension of a buffer plate, fitted to one end of the buffer plate is a C-shaped outside fastener unit. By closing the opening with the zipper, wrapping of the inside fastener unit by the outside fastener unit, and an additional C-shaped exterior wrapping strip wrapping the outside fastener unit, so the inside and outside fastener units are completely and firmly combined to completely seal the opening of a flexible container, and water is kept from seeping in, thereby achieving its sealing purposes to resist water and withstand water pressure.