Abstract： Objective： To observe the effect of acupoint application of Fuzi Dingxiang Powder on bowel preparation before colonoscopy in patients with constipation of yang deficiency type. Methods：From January to October 2024，98 patients with constipation of yang deficiency type who underwent colonoscopy in the First Affiliated Hospital of Ningbo University were selected. According to the random number table method， they were divided into the conventional group and the combination group，with 49 cases in each group. The conventional group was treated with Polyethylene glycol electrolyte solution （PEG-ELS），and the combination group was treated with acupoint application of Fuzi Dingxiang Powder while taking PEG-ELS. The scores of Boston Bowel Preparation Scale （BBPS），tolerance rate of bowel preparation，examination results，and incidence of adverse reactions were compared between the two groups. The serum indexes of brain-gut axis [cortisol （Cor），angiotensinⅡ（AngⅡ），epinephrine （E）] were detected the day before and after the examination. Results：The percentage of BBPS score ≥ 2 points and total score ≥ 6 points in left colon，transverse colon and right colon in the combination group were higher than those in the conventional group （P＜ 0.05）. The detection rate with diameter < 5 mm and total detection rate of polyps in the combination group were higher than those in the conventional group， and the examination time was shorter than that in the conventional group （P＜ 0.05）. After the examination，the levels of Cor，AngⅡ，and E in the combination group were higher than those on the day before the examination，but the levels of the above indexes in the combination group were lower than those in the conventional group （P＜0.05）. The tolerance rate of bowel preparation was 87.76% （43/49） in the combination group and 71.43% （35/49） in the conventional group，the difference being significant （P＜0.05）. In the combination group， there were three cases of transient burning sensation and one case of tingling within 30 minutes after application. The main complaint was tolerable. Without special treatment，it relieved spontaneously after 1 hour. There was no significant difference being found in the comparison of the total incidence of adverse reactions between the two groups （P＞0.05）. Conclusion：The colonoscopy pretreatment protocol of acupoint application of Fuzi Dingxiang Powder can significantly improve the quality of bowel preparation， improve the detection rate of polyps， shorten the examination time， avoid excessive activation of the brain-gut axis，thereby reducing adverse reactions，and is well tolerated.