The invention discloses an airtight thermal insulation with a large opening therein, comprising a base, a tableware box, a thermal insulation body, a zipper enclosure, an iron wire frame and a strap, wherein the side of the base has the tableware box, the top thereof has the body; the side of the body has an outer pocket, the left and right sides thereof have a handle above the pocket, the interior thereof has the inner lining; two sides of the inner lining top have a zipper tail strap extendedly, the periphery thereof has the velcro; the body top edge has a zipper enclosure; two sides of the enclosure have a side patch top, the enclosure is internally embedded with the iron wire frame comprising left and right ones. The overall structure is simple, the sealing effect is good, the large opening effect is achieved and it has certain promotion value.