Abstract: Simulating water stress with PEG-6000,the barley seedlings of ＂13PJ-118＂（drought tolerant） and ＂13PJ-108＂（drought sensitive） were treated with different concentrations of PEG-6000（5%,10%,15%,20%,25%）,and the activity of protective enzyme were determinated such as leaf SOD activity,POD activity,CAT activity.The results showed that the activity of SOD showed an increasing trend by the incressing of PEG-6000 concentration,but the activity of POD and CAT first increased and then decreased;The SOD activity could be used as the most important physiological index of drought resistance,and the POD activity,the CAT activity may be the major index.