Objective To investigated the effect of dexmedetomidine(Dex) on wake-up tests of patients undergoing scoliosis surgery.Methods Forty patients,aged 12 y-20 y,ASA Ⅰ-Ⅱ,undergoing elective scoliosis surgery were randomly divided into 2 groups:Dex group (group D,n=20)and control group (group C,n=20).Group D received loading dose of Dex 0.8 μg/kg within 10 min before induction followed by 0.2 μg·kg-1 ·h-1 throughout the surgery.Group C received equal volume of normal saline intravenously.The maintenance drugs were withdrawed at the beginning of wake-up tests.Wake-up time was recorded.BIS values and hemodynamic index,such as HR,MAP,were recorded at the time points of withdrawal and awakening.At the same time,the wake-up time and wake-up quality score,the amount of bleeding during the wake-up tests were also recorded.Results There was no significant difference in wake-up time between two groups.MAP,HR of patients in group D decreased significantly than that in control group(P<0.05) during wake-up.The wake-up quality of group D was better than that in control group(P<0.01).Conclusions Dex can increase the wake-up quality of scoliosis surgery significantly without prolonged wake-up time,meanwhile it keeps hemodynamic stable. Key words: Dexmedetomidine; Scoliosis surgery; Wake-up tests