Abstract: The study analyzed the five physiological and biochemical responses of upland rice under water stress, adopted PEG simulated water stress method and took three different drought-resistant ability of upland rice varieties‘baihuashan’,‘hangu’,‘xiaohongmi’as experimental materials to reveal the drought stress effects on physiological and biochemical characteristics of upland rice seedling. The results indicated that the activity of SOD, POD and CAT had a first rising then downward trend on 3 upland rice varieties tested under mild PEG osmotic stress, while under severe stress the activity had first a rise then a sharp decline in small amounts in most varieties tested. The effect under different stress on the enzyme activity was severe stress (named T3)＞Mild stress (named T1)＞Moderate stress (named T2), and the activity of protective enzyme was all high drought resistant varieties‘baishanhua’＞moderate drought resistant varieties‘hangu’＞droughtsensitive varieties‘xiaohongmi’under all different concentration PEG simulated water stress. MDA content showed rising trend as the degree of stress and stress time extended, and the speed of the rise was drought-sensitive varieties‘xiaohongmi’＞moderate resistant varieties‘hangu’＞high resistance varieties‘baishanhua. Soluble sucrose content showed rising trend in which high resistance varieties‘baishanhua’＞moderate resistant varieties‘hangu’＞drought-sensitive varieties‘xiaohongmi’, and T3＞T2＞T1＞T0(CK). This indicated that upland rice seedlings could adapt to drought stress by adjusting osmotic substance, decreasing water potential and improving protective enzymes activity to improve antioxidant ability under drought stress.