Objective To observe the effect of intranasal dexmedetomidine combined with mask inhalation of low‑concentration sevoflurane for enhanced CT sedation in children. Methods A total of 100 children aged 1−5 y who underwent enhanced CT were enrolled. According to the random number table method, they were divided into three groups: a chloral hydrate group (group C，n=34), a dexmedetomidine group (group D，n=33) and a dexmedetomidine combined with sevoflurane group (group DS，n=33). Children in group C were transrectally perfusioned with 10% chloral hydrate at 0.5 ml/kg, while those in group D were treated with 3 μg/kg dexmedetomidine nasal drip. The children in group DS were treated with 3 μg/kg dexmedetomidine nasal drip and mask inhalation of 2%−3% sevoflurane. Then, their Ramsay score reached 4 or more, and enhanced CT scanning was performed. The success rate of sedation in the three groups was recorded (uncompleted enhanced CT scan was defined as sedation failure). The time to achieve the expected sedation time, recovery time, and the examiner's satisfaction with sedation were recorded. The adverse events during the whole monitoring period were recorded, including hypoxia, respiratory inhibition, and decreased heart rate and hypotension. Results The success rate of sedation in group DS was 97.0%, which was higher than that in group C (73.6%) and group D (87.9%). The time to achieve the expected sedation in group DS was (4.0±0.8) min, which was significantly shorter than that in group C [(21.9 ±7.4) min, P<0.001] and group D [(32.3±8.3) min, P<0.001]. The time to achieve the expected sedation in group C was significantly shorter than that in group D [(21.9 ±7.4) min VS (32.3 ±8.3) min, P<0.001]. The recovery time in group C was (77.1±19.1) min, which were significantly longer than that in group D [(57.0±21.7) min, P<0.001] and group DS [(60.0±23.9) min, P<0.001]. There was no significant difference in the recovery time between group D and group DS [(57.0±21.7) min VS (60.0±23.9) min, P=0.262]. The examiner's satisfaction in DS group was (8.9±0.4) scores, which were significantly higher than those in group C [(7.5±2.3) scores， P<0.001],without significant difference with group DS [(8.0±1.6) scores，P=0.269]. The examiner's satisfaction in group C was significantly lower than that ub group D [(7.5±2.3) scores VS (8.0±1.6) scores，P<0.001]. A total of 5 children in the three groups showed over 20% baseline decreases in heart rate, without over 20% decreases in blood pressure. There were no cases of respiratory inhibition, hypoxia events and other adverse events. Conclusion Compared with dexmedetomidine alone or dexmedetomidine plus chloral hydrate, intranasal dexmedetomidine combined with low‑concentration sevoflurane inhalation is useful for enhanced CT sedation in children can effectively improve the success rate.