Objective:To study the stability of dexmedetomidine combined with three opioid drugs ( sufentanil, fentanil and butor-phanol) in order to guide the reasonable clinical prescription. Methods:Dexmedetomidine was respectively combined with sufentanil, fentanil and butorphanol in 0. 9% sodium chloride injection. The mixture was stored at room temperature for 0, 24, 48 and 96h, and then withdrawn for the detection of appearance, pH value, insoluble particles, and the analysis of mass spectrometry was performed. Results:Within 96 h, the prepared solutions were clear and transparent with stable pH value and qualified insoluble particles, and the results of mass spectrometry showed no new substance was generated. Conclusion:The three combination schemes are safe, reasonable and feasible in clinical application.