Objective To analyze the effect of Dezocine on the median effective dose (ED50) of Etomidate-Propofol mixture (EP mixture) and its efficacy and safety in painless gastroscopy.Methods A total of 60 patients who undergoing painless gastroscopy in Shunde Hospital of Southern Medical University from June 2019 to June 2020 were selected and divided into the Dezocine group and the control group according to random number table method,with 30 cases in each group.Patients in the Dezocine group received intravenous Dezocine 50 μg/kg before the EP mixture,and patients in the control group received only the EP mixture for anesthesia.The incidence of adverse reactions such as hypotension,injection pain,muscle tremor,nausea and vomiting,the time to reach the target anesthesia depth,the time to wake up,the time to leave the room,the time spent in examination and the ED50 were compared between the two groups during painless gastroscopy.Results The incidence of adverse reactions such as hypotension,injection pain,muscle tremor,nausea and vomiting in Dezocine group were lower than those in control group,and the differences were statistically significant (P＜0.05).The time to reach the target anesthetic depth in Dezocine group was shorter than that in control group,and the difference was statistically significant (P＜0.05).The ED50 of Dezocine group was lower than that of control group,and the difference was statistically significant (P＜0.05).Conclusion The use of Dezocine compound EP mixture has obvious effect on inhibiting visceral pain reaction in painless gastroscopy,which can effectively save the amount of drugs,reduce the social burden,reduce the incidence of adverse reactions and improve medical safety.It has good social value and is worthy of application in clinical practice.