Objective: To observe the viability, effectiveness and safety after infusion in child. Methods: Total 42 children patients were included into this study. The pain of patients was evaluated with FLACC and VAS. Moreover, the Ramesay grade method was used to evaluated anesthesia state, when the FALCC grade>4 or VAS grade>4, the morphine of 10 ug/kg was used by nurse anesthetist, the assessment was did per 10 min, after 1 h, we recorded the FALCC, VAS and Ramesay grades. Results: Within 1 h since the children went into PACU, there were no significant difference about FLACC, VAS and Ramesay score between two groups, so did the heart rate and blood pressure and the dose of morphine before drug infusion. Within 24 h during infusion, the heart rate, systolic and diastolic blood pressures were measured and performed statistics; the intra-individual variability results showed that there was no statistically significant difference about time factor, suggesting the indicators didn’t change over time. The interindividual variability results showed that P<0.05, suggesting the indicators were different as different grouping. And there was no significant difference about the interaction between time and grouping, indicating that the grouping factor didn’t change over time. 24 h after infusion, the VAS, FLACC and Ramesay score of patients were measured and performed statistics, the results showed that there was no significant difference about time and grouping factors; at the same time, the usage of morphine was recorded, the results showed that there was significant difference about the usage of morphine between the two groups from the second hour after infusion. Conclusion: Intravenous continuous infusion of dextral dexmedetomidine as adjuvant analgesia could reduce the demand of morphine effectively in children, which had good sedative effect and high safety.