A method for forming a three-dimensional pattern includes following steps. A shaped workpiece having an inner surface and an outer surface is provided, and a first photoresist layer and a second photoresist layer are respectively formed on the outer surface and the inner surface. The shaped workpiece is placed on a transparent fixture. The first photoresist layer and the second photoresist layer are exposed and developed, such that the first photoresist layer forms a patterned photoresist layer, and the second photoresist layer forms an etching protection layer. The shaped workpiece is etched to form the three-dimensional pattern on the outer surface of the shaped workpiece. The patterned photoresist layer and the etching protection layer are removed.