The study is being conducted to evaluate the efficacy, safety and the population pharmacokinetic characteristics of dexmedetomidine hydrochloride nasal spray for preoperative sedation in children

Inclusion Criteria:

1. Able and willing to provide a written informed consent
2. Male or female
3. Subjects requiring elective general anesthesia surgery
4. Conform to the ASA Physical Status Classification
5. Meet the weight standard

Exclusion Criteria:

1. Not suitable for nasal spray
2. Pediatric populations requiring special care or court/social welfare supervision
3. Subjects who had been under general anesthesia were randomized
4. Subjects with mental disorders and cognitive impairment；Subject with a history of epilepsy
5. Subjects with previous abnormal behavior after medication
6. Subjects with cardiovascular disease
7. Clinically significant abnormal clinical laboratory test value
8. Subjects whose hemoglobin is below the lower limit of normal
9. Subjects who have either an adrenergic receptor agonist or an antagonist were randomized
10. Participated in clinical trials of other drugs before screening (accepted experimental drugs)
11. A history or possibility of difficult airway
12. History of hypersensitivity to drug ingredients or components
13. Other circumstances that the investigator judged inappropriate for participation in this clinical trial