Objective To observe the application effect of one-piece ostomy bag in the management of drainage tube displacement after percutaneous transhepatic cholangial drainage (PTCD). Methods A total of 46 patients undergoing PTCD in our hospital from May 2020 to August 2021 were selected as the research objects and randomly divided into the control group and the observation group, with 23 cases in each group. The control group was treated with conventional gauze dressing under pressure, and the observation group was treated with one-piece ostomy bag. The daily dressing change times, changing clothes times, pain score, comfort score, sleep quality, irritant dermatitis grading, complication rate and quality of life score were compared between the two groups. Results The times of dressing change and changing clothes in the observation group were less than those in the control group (P＜0.05). The scores of pain and sleep quality in the observation group were lower than those in the control group, and the comfort score was higher than that in the control group (P＜0.05). The incidence of grade Ⅰ irritant dermatitis in the observation group was higher than that in the control group, and the incidence of grade Ⅱ and Ⅲ irritant dermatitis was lower than that in the control group (P＜0.05). The incidence of complications in the observation group was 8.70%, which was lower than 26.08% in the control group (P＜0.05). The quality of life scores of the two groups were higher than those before treatment, and the observation group was higher than the control group (P＜0.05). Conclusion The application of one-piece ostomy bag in the management of drainage tube displacement after PTCD is effective, which can reduce the number of dressing change and changing clothes daily, relieve the pain score, improve the sleep quality and comfort, reduce the incidence of irritant dermatitis and complications, and improve the quality of life of patients.