Abstract: The present invention relates to a waterproof structure for computer key switch, especially a waterproof structure which comprising an upper protective cap and a lower protective cap, wherein the upper protective cap protecting the part of the computer key switch above the printed circuit board, the post of the computer key can be inserted into a fitting hole of the upper protective cap, the inner wall of the fitting hole contacting tightly with the post of the computer key, the lower protective cap covering the part of the computer key under the printed circuit board, therefore the whole computer key switch can be protected by the waterproof structure so as to prevent water or dust from penetrating into the computer key switch, when inserting the post into the fitting hole of the upper protective cap, the fitting hole can be supported with a leading mold so as to provide a quick inserting method.