Abstract: The effects of peanut yield-increasing agent on morphology and physiology of peanut plants were studied. The application of peanut yield-increasing agent could shorten the height increasing the lodgeresistance and yield of the peanut plants. This agent increased the photo-synthetic rate,the content of chlorophyll and the ratio of chlorophyll a/b in the peanut leaves. It also promoted the development of root system and regulate the relationship between vegetative growth and reproductive growth, and increased the ratio of the distribution of photo-synthetic substances to the legume and seeds.