Abstract: Objective To observe the effects of different doses of dexmedetomidine by nasal atomization on negative postoperative behavioural changes of children undergoing eyelid surgery under general anesthesia. Methods A total of 192 children (89 males and 103 females, aged 3-7 years, weighing 12-40 kg, ASA grade Ⅰ-Ⅱ) underwent eyelid surgery under general anesthesia were enrolled in this study and were equally assigned into four groups (n=48 in each group) using a random number table method: a control group (group C), a dexmedetomidine 1 μg/kg group (group D₁), a dexmedetomidine 2 μg/kg group (group D₂) and a dexmedetomidine 3 μg/kg group (group D₃). The experimental groups ( groups D₁, D₂ and D₃) received different doses of dexmedetomidine (1, 2 or 3 μg/kg, respectively) nasal atomization in the induction room accompanied by their parents, and the control group (Group C) received 0.02 ml/kg normal saline nasal atomization. The preoperative sedation score, emotion score due to separation from parents, mask acceptance score, the number of cases of restlessness in the post-anesthesia care unit (PACU), agitation score, extubation and recovery time, and perioperative adverse events (bradycardia, laryngospasm) were recorded. The Post Hospitalization Behavior Questionnaire (PHBQ) was used to evaluate the behavior of the children after operation and discharge at 1, 7 and 30 d after operation. Results Compared with group C, the incidence of adverse behavior changes was significantly lower in groups D₁, D₂ and D₃ at 1 d after surgery (P<0.05). Compared with group C, the incidence of adverse behavior changes at 7 d after operation in groups D₂ and D₃ was significantly reduced (P<0.05). At 1 and 7 d after surgery, the incidence of separation anxiety and sleep anxiety in group Ds was significantly lower than that in group C (P<0.05). There was no statistically significant difference in the incidence of other behavioral changes among the 4 groups (P>0.05). Compared with group C, Ramsay Sedation Score, separation emotion score and mask acceptance score of children in groups D₁, D₂ and D₃ were significantly increased, while postoperative agitation score was significantly decreased (P<0.05). The wake-up time of children in group D₃ was significantly longer than that of the other 3 groups (P<0.05). There was no significant difference in extubation time, bradycardia and laryngospasm among the 4 groups (P>0.05). Conclusions Preoperative 2 μg/kg dexmedetomidine by nasal atomization can effectively reduce the incidence of postoperative adverse behavior changes in children under general anesthesia.