Objective To retrospectively analyze the clinical efficacy of the RAP（Ruxolitinib，Azithromycin，and Pirfenidone） hormone-free regimen in the treatment of moderate to severe BOS and its influencing factors. Methods This study included 14 patients who developed moderate to severe BOS after undergoing allo-HSCT at our center from January 1，2018 to December 31，2023. These patients were retrospectively analyzed for the clinical efficacy of the RAP hormone-free regimen and its influencing factors. Results ①The overall response rates at 3，6 and 12 months of treatment were 50.0%，57.1%，and 50.0%，respectively. At the six-months post RAP regimen，the FEV1% predicted value（t=2.187，P=0.033），6 minute walk test（t=2.338，P=0.023），ECOG physical state score（t=2.681，P=0.013） and cGVHD severity（Z=2.155，P=0.032） of 8 patients who responded to the RAP treatment were significantly improved. ②Survival： During a median follow-up of 13 months，5 patients（35.7%） died of severe pneumonia complications. Univariate analysis showed that the extended course of RAP treatment was correlated with a trend of survival improvement（P=0.089）. ③Glucocorticoid exposure：all 14 cases had a long-term history of glucocorticoid use，8 cases（57.1%） discontinued glucocorticoid use within 1 month，and 2 cases reduced their dose by more than 50%. ④The safety profile was favorable，and the main adverse reactions were gastrointestinal reactions and hematological toxicity. Conclusion The RAP hormone-free regimen shows a favorable effect in the treatment of moderate to severe BOS. It allows for the rapid withdrawal of glucocorticoids and improves the quality of life and long-term survival of patients. However，it needs to be further verified by prospective studies due to its small sample size and retrospective design.