A waterproof method for an electronic device and a waterproof electronic device are provided. The electronic device comprises a printed circuit board, which comprises a board, a plurality of electrical elements and a button device. The waterproof method comprises the following steps: applying a first non-solid adhesive to cover the button device directly, curing the first non-solid adhesive to form a first waterproof layer, applying a second non-solid adhesive to at least cover the electrical elements directly and curing the second non-solid adhesive to form a second waterproof layer. In the end, assembling the printed circuit board, sealed with the waterproof layers, into a case to form the waterproof electronic device.