Referring to FIG. 3 and FIG. 4, when users push the handle 232, the movable latch lid 230 moves along the direction of extension of the passages 231 to reach a fastening position, such that the latch portions 233 in the form of bumps are latched into the fastening grooves 111, so as to fix the waterproof lid structure 200 in place and prevent it from opening. Referring to FIG. 5 and FIG. 6, to open the waterproof lid structure 200, users push the handle 232 reversely, such that the movable latch lid 230 moves to an unlocked position, triggering the separation of the latch portions 233 from the slots of the fastening grooves 111. Therefore, the latch portions 233 and the fastening grooves 111 address the durability issue better than hook-based engagement in terms of the fixation of the waterproof lid structure 200. In addition, the waterproof lid structure 200 has the supportive sheet metal 211 and thus is structurally stronger than its conventional counterparts which are entirely made of plastic, and the waterproof lid structure 200 is not predisposed to damage and deformation even after long use.