Objective: To explore the clinical application effect of combined respiratory rehabilitation training combined with budesonide formoterol powder inhalation on asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS). Methods: Totally 70 patients with ACOS in the hospital from May 2024 to February 2025 were selected, and were divided into inhalation group (n=35, budesonide formoterol inhalation) and rehabilitation training combined group (n=35, combined respiratory rehabilitation training on the basis of inhalation group) by random number table method. After the end of treatment, the clinical efficacy, pulmonary function indexes, inflammatory factors, blood gas indexes, fractional exhaled nitric oxide (FeNO), quality of life and occurrence of adverse reactions were compared between the two groups. Results: The total effective rate in rehabilitation training combined group (94.29%) was significantly higher than that in inhalation group (77.14%) (P<0.05). After treatment, the forced vital capacity (FVC), forced expiratory volume in one second (FEV1), arterial partial pressure of oxygen (PaO2) and oxygen saturation (SaO2) in the two groups were significantly increased (P<0.05) while the tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), FeNO and chronic obstructive pulmonary disease assessment test (CAT) score were significantly decreased (P<0.05), and the above indexes were significantly different between the two groups (P<0.05). Conclusion: The application of combined respiratory rehabilitation training combined with budesonide formoterol powder inhalation has a significant effect on ACOS, and it can effectively improve the pulmonary function and blood gas indexes, reduce inflammatory response, and promote the significant improvement of quality of life.