The present invention relates to a luggage, having an integrated structure. The luggage includes a one-piece shell, which is constructed from a single molding to form a continuous structure and has at least a top wall and two opposing side walls. The top wall has two sloping curved corners which are sloped and curved toward the cover of the luggage and the respectively abutting side wall. The present also invention provides a method of manufacturing the luggage. The method includes the steps of assembling a family mold to form a mold cavity, injecting mold material into the mold cavity to make the one-piece shell for the luggage, and removing the family mold. The family mold includes an inner mold tool and an outer mold tool, and the step of removing the family mold includes the steps of removing the outer mold tool first, and then, removing the inner mold tool.