The invention discloses a method for breeding a stress-tolerance plant and a special DNA piece thereof. The invention provides a fusion protein which comprises chloroplast transit peptide and phosphoric acid fucose synthetase, wherein, the chloroplast transit peptide is positioned at an amino terminal of the fusion protein, the phosphoric acid fucose synthetase is positioned at a carboxyl terminal of the chloroplast transit peptide. The fusion protein also comprises phosphoric acid fucose phosphatase which is positioned at the carboxyl terminal of the phosphoric acid fucose synthetase. The coding genes of the fusion protein are led into the plant, thereby evidently improving the stress tolerance of the plant. The fusion protein and the coding genes are significant to the breeding of stress-tolerance plant, particularly the abiotic stress -resistance plants such as drought tolerance and/or salt-tolerance plants, thereby improving the crop yield.