In order to explore the adaptability characteristics of oats glume under water deficit,this paper used different drought resistance oat varieties ‘Bayou 3’(water sensitive) and ‘Mengyan 1’(drought-resistant) as test materials,to study osmotic regulation and anti-oxidation ability of oat glumes at heading stage and filling stage under water stress by pot experiment.The results showed that:(1)Water stress treatments could significantly promote the content of osmolytes among different drought-resistance varieties.The accumulation level of drought-resistant variety was higher than that of water sensitive one,and the reaction of two osmolytes to stress was more sensitive at heading stage than that of filling stage.(2)Water stress treatments could reduce the superoxide dismutase (SOD) and peroxidase(POD) activities of glume among different drought-resistance varieties in both heading and filling stage.The protective enzyme activities of drought-resistant variety were higher than that of water sensitive variety.The SOD activity reduction rate of drought-resistant variety was significantly lower than that of water sensitive variety,while the POD activity decreased with no obvious difference between the two varieties.(3)Water stress led to methane dicarboxylic aldehyde (MDA) content and the relative electrical conductivity increased significantly,and the change of water sensitive variety was greater than that of drought-resistant variety.(4)Water stress decreased the grain yield per plant.The yield reduction rate of drought-resistant variety was lower than that of water sensitive variety under moderate stress and severe stress in the same period.Under water stress,the reduction of ‘Bayou 3’ was from 4.54% to 30.29%,while ‘Mengyan 1’ was from 6.69% to 23.54%.Therefore,the drought resistance of oat varieties to adapt to water stress by strengthening the osmotic adjustment and antioxidation ability reduced the golem cell membrane damage,which helps to minimize the damage of water stress,conducive to stable yield.