The present invention is aimed to provide a crown for waterproof cap. The crown (20) consists of six panels (21˜26), inside the crown there are diagonal seams (27) intersected. These seams can be sealed by stickers (41˜43) contain thermoplastic membrane (40). Whereby the seams are connected with panels (21˜26) to achieve waterproof effects. In manufacturing, high frequency circular wheel cuts and melts between panels (21˜26), leftovers cut off and thrown out, piled sides of panels are welded to form a seam (27). Stickers contain thermoplastic membrane can be heated inside the crown between two adjacent panels, where a roller rolls over to press down the sticker to cover up the seams. Thereby, a crown is completed.