Abstract: The yield and quality of American sweet pea was studied by using the plant growth regulator DTA-26 in Beijing and Tianjin in 2000 and 2001. The plantsw as treated with DTA 26 and clean water as CK in the experiment. The result showed that the fresh and dry weight of plant and the weight of fruit per plant were increased by DTA 26, the yield was improved. The amount of water-so luble sugars and water-so luble protein and free am ino-acids were increased, thus improved the nut ritional quality of the bean. At the same time, the activity of root and the content of chlorophyll were increased. The experiment proved that the plant growth regulator DTA 26 imp roved the quality and yield of sweet pea.