Objective To investigate the preventive and therapeutic effects of different doses of penehyclidine hydrochloride preoperative medication on the catheter -related bladder discomfort during general anesthesia recovery period.Methods 160 adult patients who underwent general anesthesia for elective surgery were randomly dividided into four groups.40 patients in each group received intravenous injection 30min before surgery with penehyclidine hydrochloride 0.005mg/kg (group A),0.010mg/kg (group B),0.015mg/kg (group C),or normal saline (group D).All patients were catheterized with a 12 Fr Foley's catheter and the balloon was inflated with 8mL normal saline after anesthesia induction .The bladder discomfort was assessed during recovery in the post -anesthesia care unit .The severity of bladder discomfort was graded as mild , moderate and severe .Results The incidence of moderate and severe bladder discomfort in group B and group C (group B:20.0％,5.0％;group C:12.8％,2.5％) were significant lower compared with group A and group D ( group A:38.5％,12.8％;group D:46.0％ 15.4％) (χ2 =7.834, 6.764,8.163,14.172,8.362,6.943,15.413,17.512,all P<0.05).There was no significant difference between group B and group C , group A and group D .Conclusion Hydrochloride penehyclidine preoperative administration with 0.010mg/kg or 0.015mg/kg can effectively control the incidence of catheter discomfort during general anesthesia recovery period and 0.010mg/kg is appropriate for the elderly .