Objective To observe the effect of different doses of dexmedetomidine on catheter ⁃ related bladder discomfort（CRBD），to explore the appropriate dose of dexmedetomidine during operation. Methods A total of 303 male patients undergoing elective surgery under general anesthesia and planned to insert catheter were selected and randomly divided into four groups：normal saline control group（group A），dexmedetomidine 0.2 μg/（kg·h） group（group B），0.4 μg/（kg·h）group（group C），and 0.6 μg/（kg·h）group（group D）. Groups B，C and D were infused with loading dose of dexmedetomidine 1 μg/kg before induction（completed by intravenous pumping within 10 min），and then were continuously pumped with 0.2 μg/（kg·h），0.4 μg/（kg· h），0.6 μg/（kg·h）respectively. Group A was given the same amount of normal saline. The infusion was stopped until 30 minutes before the end of the operation. The incidence and severity of CRBD were evaluated at the postanesthesia care unit（PACU）（T0）， 1 h（T1），6 h（T2），and 24 h（T3）after operation. Intraoperative drug use and postoperative adverse events were recorded. Results The incidence of CRBD，at T0，T2，there were differences between group A and B，group A and C，and group A and D（P < 0.05）. At T1，there were differences between group A and group B，group A and group C，group A and group D，and between group B and group D（P < 0.05）. At T3，there were differences between group A and group C，and group A and group D（P < 0.05）. At T0，T1 and T2，the incidences of moderate to severe CRBD in group D were statistically different from group A（P < 0.05）. The NRS scores of the four groups at T0，T1 and T2 were statistically significant（P < 0.05）. At T3，the control group was higher than that of the dexme⁃ detomidine group，but there was no significant difference between the dexmedetomidine groups. The use of remifen⁃ tanil and propofol decreased with the increase of dexmedetomidine dose，which was statistically significant among the four groups. There was no significant difference in the incidence of adverse reactions among the four groups （P > 0.05）. Conclusions Intraoperative administration of dexmedetomidine can reduce the incidence of postoper⁃ ative CRBD，The dose of 0.6 μg/（kg · h）can reduce the incidence and severity of CRBD，and this dose can improve the comfort of patients without related adverse reactions.