Abstract: A mask with a three-dimensional structure provides a one-piece structure with an upper portion, the middle portion, and a lower portion. A molded notch is located at both nasal bridge of the upper portion and chin of the lower portion. The upper portion and lower portion are reversely folded so as to form a pleat for supporting the middle portion as a three-dimensional structure mask. The three-dimensional structure mask meets the facial configuration design for accommodating to different facial shapes. Furthermore, the mask with a three-dimensional structure has a normal range of elasticity to conform to certain facial contours, therefore, decreases leakage occurrence, and increases filtration rate in a high pollution environment. More, the upper portion and the lower portion of the mask are folded in a reverse direction for avoiding a contacting pollution from touching the inner surface.