Abstract：Objective：To observe the clinical efficacy of Sanzi Xiapo Decoction combined with western medicine in treating acute exacerbation of asthma-COPD overlap（ACO） with phlegm-heat accumulation in lung syndrome. Methods：Sixty-four patients with acute exacerbation of ACO with phlegm-heat accumulation in lung syndrome treated at the Department of Pulmonary Diseases，Dongguan Hospital of Guangzhou University of Chinese Medicine from July 2023 to April 2025 were divided into the treatment group and the control group using the random number table method， with 32 cases in each group. The control group was treated with western medicine，and the treatment group was treated with Sanzi Xiapo Decoction based on the treatment of the control group. Both groups were treated for seven days continuously. Changes in traditional Chinese medicine syndrome scores， partial pressure of carbon dioxide（PCO2）， partial pressure of oxygen（PO2），white blood cell count（WBC），eosinophil count（EOS），fractional exhaled nitric oxide（FeNO），interleukin-6（IL-6），and tumor necrosis factor-α（TNF-α）were observed before and after seven days of treatment. Results： After seven days of treatment， both groups showed reductions in traditional Chinese medicinesyndromescoresandlevelsofPCO2，WBC，EOS，FeNO，IL-6，andTNF-α（P＜0.05），withgreaterreductions in the treatment group（P＜0.05）. After seven days of treatment， PO2 levels increased in both groups compared with those before treatment（P＜0.05）， with higher levels in the treatment group（P＜0.05）. Conclusion： Sanzi Xiapo Decoction combined with western medicine alleviates clinical symptoms and airway inflammation， improves lung ventilation and oxygenation in patients with acute exacerbation of ACO with phlegm-heat accumulation in lung syndrome.