Hypoxia is a common adverse event during sedated hysteroscopy for assisted reproduction, and it is more likely to occur in overweight or obese patients. In sedated gastroscopy, the incidence of hypoxia with remimazolam is lower than that with propofol. The present study is a single-center, randomized, single-blind, controlled clinical trial. Overweight or obese patients undergoing sedated hysteroscopy for diagnosis and treatment, with ASA grade I or II, were selected as subjects and randomly divided into an experimental group and a control group, with 300 subjects in each group. Sedation induction and maintenance are performed using remimazolam or propofol combined with remifentanil, respectively, to compare the incidence of severe hypoxia during surgery between the two groups of patients.