Abstract： Objective： To observe the clinical effect of Xuanbai Chengqi Decoction combined with mechanical ventilation on senior patients with acute exacerbations of chronic obstructive pulmonary disease （AECOPD） of phlegmheat obstructing the lung type and its effect on intestinal flora and gastrointestinal mucosal barrier function. Methods： A total of 70 senior patients with AECOPD of phlegm-heat obstructing the lung type who underwent mechanical ventilation in the emergency intensive care unit of Wuyi County First People's Hospital from January 2022 to June 2024 were selected as the study subjects. All patients were divided into the control group and the observation group according to the random number table method， with 35 cases in each group. The control group was treated with conventional western medicine， and the observation group was additionally treated with Xuanbai Chengqi Decoction based on the treatment of the control group. The clinical effects， intestinal flora， levels of serum gastrointestinal mucosal function indexes [D-lactic acid and diamino oxidase （DAO）] and inflammatory indexes [interleukin-6（ IL-6）， C-reactive protein （CRP） and procalcitonin （PCT）] and incidence of adverse reactions were compared between the two groups. Results： The total effective rate was 94.29% （33/35） in the observation group and 71.43% （25/35） in the control group，the difference being significant （P＜0.05）. Before treatment，there were no differences being found in the comparison of the numbers of Enterococci， Enteric Bacilli， Lactobacilli and Bifidobacterial between the two groups （P＞0.05）；after treatment，the numbers of Enterococci and Enteric Bacilli in the observation group were less than those in the control group （P＜0.05），and the numbers of Lactobacilli and Bifidobacteria were greater than those in the control group（ P＜0.05）. Before treatment，there were no significant differences being found in the comparison of the levels of D-lactic acid and DAO between the two groups （P＞0.05）；after treatment，the levels of D-lactic acid and DAO in the observation group were lower than those in the control group （P＜0.05）. Before treatment，there were no significant differences being found in the comparison of the levels of IL-6， CRP and PCT between the two groups（P＞0.05）；after treatment，the levels of IL-6，CRP and PCT in the observation group were lower than those in the control group（ P＜0.05）. The incidence of adverse reactions was 5.71%（ 2/35） in the observation group，and that of 22.86% （8/35） in the control group， the difference being significant （P＜0.05）. Conclusion： Xuanbai Chengqi Decoction combined with mechanical ventilation has a definite curative effect on senior patients with AECOPD of phlegm-heat obstructing the lung type，which can improve the intestinal microecology and the gastrointestinal mucosal function，down-regulate the level of inflammatory responses and reduce the adverse reactions.