Objective To analyze the relationship between ambulatory blood pressure (ABP) and cognitive function in elderly hypertensive patients with leukoaraiosis (LA).Methods Eighty elderly hypertensive patients with LA underwent 24 h ABP monitoring to record their 24 h SBPV,DBPV,AASI,and APPI.The patients were scored according to the MMSE Scale.Results The 24 h SBPV,DBPV,AASI,and APPI were significantly higher in degrees 1,2,3 of LA than in degree 0 of LA (P＜0.05),in degrees 2,3 of LA than in degree 1 of LA (P＜0.05),and in degree 3 of LA than in degree 2 of LA (P＜0.05).The MMSE Scale score of memory,attention,counting,recall,language and the total score were significantly lower in degrees 2,3 of LA than in degrees 1,2 of LA (P＜0.05).The 24 h SBPV,DBPV,AASI,and APPI were negatively related with the MMSE Scale score (r=-0.8697,P=0.000;r=-0.6709,P=0.002;r=-0.8373,P=0.000;r=-0.5991,P=0.007).Conclusion The severer the LA is,the higher the 24 h SBPV,AASI and APPI are.The 24 h SBPV and AASI can thus be used as the indicators of LA and cognitive function impairement.