Abstract: Objective To investigate the effect of hypertension and its drug treatment on cognitive functions of pilots. Methods Cognitive functions of 13 hypertension pilots without complications and 10 pilots with their blood pressure returned to normal after treatment with hypertension-reducing drugs were tested,including critical flicker frequency,selective reaction times,space location memory span,attention focusing ability,and vigilance.Thirteen healthy pilots at the similar age served as controls. Results The critical flicker frequency,attention focus ability,and scores of space location memory span of hypertension pilots were significantly lower than those of controls（P＜0.05,P＜0.01,P＜0.01）,while their reaction time to red,yellow and green lamps were significantly longer than those of controls（P＜0.01）,and their total error rate in vigilance test was higher than that of controls（P＜0.01）.There was a significant difference in cognitive functions of pilots between hypertension group and hypertension treatment group（P＜0.05,P＜0.01）. Conclusion The cognitive functions of hypertension pilots are impaired at different degrees.Importance should be attached to this problem at medical evaluation of pilots.