Abstract: ［Abstract］Objective　To compare the feasibility and efficacy between dexmedetomidine and midazolam in herniorrhaphy surgery for older patients. Methods　Sixty American Society of Anesthesiology（ASA）grade Ⅰ～Ⅱpatients， treated by herniorrhaphy surgery under local anesthesia，were randomly divided into dexmedetomidine group（n＝30） and midazolam group（n＝30）.Patients in dexmedetomidine group were given dexmedetomidine at a loading dose of 1μg/kg for 10 min，then they were injected continuously by 0.4 μg/(kg·h)，whereas midazolam group were given midazolam at a loading dose of 0.06 mg/kg， then 0.04 mg/(kg·h) injected continuously.The mean blood pressure（MAP）and heart rate（HR） were recorded before infusion（T0），incision of skin（T1），15min（T2）and 30 min（T3） after administration and when sutured skin （T4），adverse reaction were also assessed. Results The difference of sedation level was not significant between the two groups（P＞0.05）.Compared with T0 ，the decrease of HR was significantly more in dexmedetomidine group from T1 to T4（P＜0.05）. Compared with midazolam group ， the decrease of HR was significantly more in dexmedetomidine group from T1 to T4（P＜0.05）. Compared with dexmedetomidine group，the rate of respiratory depression and restlessness were more in midazolam group，but bradycardia was lower（P＜0.05）.Conclusions Dexmedetomidine is a comparable alternative to midazolam for sedation in herniorrhaphy surgery under local anesthesia. It is associated with better respiration and lower restlessness but with a high incidence of bradycardia.