We studied growth and physiological responses of Ambrosia trifida L. under the different light condition. Ambrosia trifida L. is Korean invasive species. For study, we selected the two spot (T1 and T2) in the Kongju National University. In each spots, we investigated growth and physiological responses in the more light environment (L) and in the less light environment (S). it makes 4 research spot (T1-L, T1-S, T2-L and T2-S). and first, we estimate light intensity (Lux) in each research spots. then take data on the growth responses which are a shoot height, a number of leaves, a leaf width and a leaf length. Also, we get some physiological data which are a photosynthetic rate, a transpiration rate, a stomata conductance, water use efficiency, chlorophyll content, photochemical efficiency of photosystem II (Fv/Fm). And, analysed them by using one-way ANOVA. As a results, the shoot height, No. of leaves, Leaf width and Leaf length were recorded relatively high in the spot of the most light quantity and in the spot of the least light quantity. In the physiological responses, the more light quantity was increased, the more photosynthetic rate, transpiration rate and stomatal conductance were increased. Fv/Fm, the photochemical efficiency of photosystem II, was the least recorded in the spot of the most light quantity. These results show Ambrosia trifida grow well in the spot of the most and the least light quantity but it grown in the shade has the less environmental stress.l