Abstract. purpose: To compare the sedation effects of two intranasal methods of dexmedetomidine for magnetic resonance imaging (MRI) in children. Method: 40 children for MRI were randomly divided into two groups, namely 20 cases for each group: nasal drip group(group A)and nasal spray group(group B). Group A and group B received intranasal dexmedetomidine of 1.5 ug/kg by two methods. Monitoring the HR, SpO2, RR and inspection time of the two groups so as to observe the sedation effects and Ramsay sedation score while recording the adverse reactions. Results: There was no significant difference in the HR, SpO2, RR between the two groups at the same time point(P>0.05). Compared with group A,the timeto-fall-asleep in group B was shorter and the adverse reactions significantly decreased(P<0.05).Conclusion: Compared with nasal drip,nasal spray dexmedetomidine by MAD can shorten the time-to-fall-asleep and reduce adverse reactions for MRI in children.