Objective To evaluate the effect of remazolam on hemodynamics in patients undergoing painless colonoscopy.Methods In this prospective and randomized controlled study,eighty patients aged 18~65 years with American Society of Anesthesiologists(ASA)Grade Ⅰ~Ⅲ were scheduled for a colonoscopy.All patients were randomly assigned into the group P and the group R(n=40 each).Patients in the P group received an intravenous injection of propofol 1.5 mg/kg and patients in the R group were induced by an intravenous injection of remazolam 7 mg.Both groups received an intravenous injection of sufentanil 0.1 μg/kg.Additional drugs were added to maintain sedation depth MOAA/S score≤3 in case of movement and obvious swallowing.Mean arterial pressure,heart rate,SpO2,and respiratory rate were recorded in two groups at different time points.The time of anesthesia induction,colonoscopy,awakening,and PACU observation were also recorded.The case number of hypotension,hypoxia saturation,and airway obstruction during the operation were observed.Results The mean arterial pressure in the group P was lower than that in group R at T2,T3,and T5 time points after anesthesia(P<0.05).The fluctuation values of blood pressure and heart rate in the group R during anesthesia were significantly lower than those in the group P(P<0.05).Compared with the P group,the emergence time and discharge time in the R group were shorter(P<0.05),and there was no significant difference in induction time and colonoscopy time between the two groups.Compared with the group P,the incidence of hypotension in group R was lower(P<0.05).Conclusion The application of remazolam in painless colonoscopy can ensure the stability of hemodynamics and the sedative effect is ideal.