What is known and objective:To compare the effectiveness and safety of remimazolam tosylate and propofol for hysteroscopy.Methods: From November 2020 to June 2021, a total of 90 patients who underwent hysteroscopy were prospectively enrolled in this study. The patients were randomly assigned to three groups: propofol group (group A), low-dose remimazolam tosylate group (group B), and high-dose remimazolam tosylate group (group C), with 30 cases in each group. All cases received intravenous sufentanil 0.1ug/kg for analgesic preconditioning. Patients in group A were given 2 mg/kg propofol intravenously, and maintained at a rate of 5 mg/kg/h. Patients in groups B and C were given intravenous remimazolam tosylate 0.25 mg/kg. Group B was maintained with remimazolam tosylate at a rate of 0.48 mg/kg/h, while group C was at a rate of 0.6 mg/ kg/h. The changes of heart rate (HR), mean arterial pressure (MAP) and saturation of peripheral oxygen (SpO2) were recorded after admission (T0), 1 min after anaesthesia (T1), dilation of the uterine cavity (T2), and the end of hysteroscopy (T3). In addition, Observer's Assessment of Alertness/Sedation Scale (OAA/S) at 1 min, 3 min, and 5 min after hysteroscopy, the incidence of adverse events, and the time from the end of the hysteroscopy to reach the discharge standard, were recorded. Results and discussion:The success rate of sedation in each group was 100%. After administration, the adverse event incidence in group A was significantly higher than that in groups B and C (p < 0.05, respectively). Compared with propofol, remimazolam tosylate did not cause injection pain, had less impact on haemodynamics and caused less respiratory depression.What is new and conclusion: Remimazolam tosylate and propofol have similar success rates for painless hysteroscopy, and both can provide safe and effective sedation. The safety of remimazolam tosylate for hysteroscopy appears to be better than that of propofol.