Abstract: Objective: To study the application of dexmedetomidine combined with sufentanil in painless ultrasound gastroscopy and its influence on patients’ circulatory system. Methods: 108 cases of patients who underwent painless ultrasound gastroscopy in our hospital from October 2016 to December 2017 were selected as the subjects of this study. All the patients were divided into control group and study group by reference to a random number table method, with 54 cases in each group. The patients in the control group underwent generalized ultrasound gastroscopy, and the patients in the study group received dexmedetomidine plus sufentanil for anesthesia and analgesia. The analgesic sedative effect, the degree of pain, the changes of circulatory system and the incidence of adverse reactions before and after the examination were compared. Results: The Ramsay sedation score of the study group was higher than that of the control group, and the VAS score was lower than that of the control group (P<0.05). There were no significant differences in SpO2, HR, SBP and DBP between the two groups before and after the examination (P>0.05). In the ultrasound gastroscopy, the SpO2 index of the study group was higher than that of the control group, and the HR, SBP and DBP indexes were lower than the control group (P<0.05). The overall incidence of adverse reactions in the study group was 7.4% (4/54), which was lower than that in the control group (38.9%, 21/54) (P<0.05). Conclusion: Dexmedetomidine combined with sufentanil has a significant effect on painless ultrasound gastroscopy. It has high safety, can enhance the analgesic sedative effect, maintain the stability of the circulatory system, and is worthy of clinical promotion.