Abstract: The physio ecological response of spring wheat root under different water and nigrogen conditions was studied with soil column experiment. The results indicated that rational application of nitrogen fertilizer(urea 600kg/hm2) could increase total root weight as well as root weight in deep soil layers, improve water relation of root, and enhance stability of root cellular membrane. Hence it is helpful for increasing drought resistance of wheat. The root increase in top soil layers by overusing nitrogen fertilizer(urea 1500kg/hm2) had little role for drought resistance. Under serious water stress, nitrogen fertilizer overuse might make percentage of rupture root cellular membrane increased, water relation of root worsen and water retention capacity decreased, thus drought resistance of wheat decreased.