A housing of a handheld electronic device includes a front and a rear shell, a bottom cover, a cover body, and a battery cover. A bearing portion and a battery receiving room are formed above and below the backside of the rear shell. A waterproof structure comprises a main body gasket, a cover body gasket, and a battery cover gasket. The top and bottom ends of the main body gasket are connected to a top gasket and a bottom cover gasket. The main body gasket and the top gasket are embedded at the adjoining profile and the topside between the front and rear shells. The bottom cover gasket is embedded between the bottom side of the housing and the bottom cover. The cover body gasket is embedded between the cover body and the bearing portion. The battery cover gasket is embedded between the battery receiving room and the battery cover.