Inclusion Criteria:  2 years old ≤age<18 years old, regardless of gender; General anesthesia is planned; ASA score grade I ~ II; 4）Able to sign the informed consent.  Exclusion Criteria:  Children with general anesthesia contraindications; With diseases that are not suitable for the study in the scheme; Abnormal liver and kidney function in screening stage; Abnormal coagulation function; Serum electrolyte abnormality; Subjects intolerant or allergic to the study drugs; Recently received other narcotic drugs or other drugs that affect the metabolism of study drugs; The child thought to be unsuitable for the study, as determined by the investigator.