Abstract: Background　Chest physiotherapy (CPT) is a crucial nursing intervention for preventing pulmonary complications in mechanically ventilated patients following surgery within the intensive care unit (ICU), and it plays a significant role in the prevention of ventilator-associated pneumonia (VAP). Objective　To construct a comprehensive chest physiotherapy program for ICU patients undergoing mechanical ventilation after surgery and evaluate its application effect. Methods　Using the Behavior Change Wheel as the theoretical framework, a comprehensive chest physiotherapy plan for postoperative ICU patients on mechanical ventilation was developed through literature analysis and expert validation. The effectiveness of the intervention was evaluated through a randomized controlled trial. From November 2024 to January 2025, postoperative mechanically ventilated patients admitted to the Surgical ICU at the First Medical Center of PLA General Hospital were randomly assigned to experimental group (a comprehensive chest physiotherapy program based on the Behavior Change Wheel theory) and control group (routine care). The intervention continued until patients were transferred out of the ICU. The incidence of VAP, duration of mechanical ventilation, and length of ICU stay were compared between the two groups. Four process indicators were also assessed: patient satisfaction, patient cooperation during CPT, incidence of adverse events during CPT, and Glasgow Coma Scale (GCS) and cough scores on days 2 and 4 of the intervention. Results　A total of 64 patients were enrolled for assessment; 8 were excluded, and 56 completed the trial (29 in the experimental group and 27 in the control group). The mean age was (67.6±14.5) years in the experimental group versus (69.7±10.8) years in the control group, with male proportions of 75.9% (22/29) versus 74.1% (20/27), showing no significant differences (P＞0.05). Although the incidence of VAP was numerically lower in the experimental group (3.4% vs 22.2%), the difference was not statistically significant (P=0.110). The duration of mechanical ventilation in the experimental group was significantly shorter than that in the control group M(P25, P75): 28.17 (26.10, 51.78) h vs 111.66 (50.88, 153.81) h, P＜0.001, as was the length of ICU stay 69.70 (50.65, 94.37) h vs 136.67 (50.90, 145.80) h, P＜0.001. Furthermore, the experimental group exhibited significantly higher patient satisfaction scores and CPT compliance scores compared to the control group satisfaction: 4 (3, 4) vs 3 (2, 3), Z=-5.218; CPT compliance: 2.5 (2.4, 2.7) vs 1.5 (1.17, 1.65), Z=-5.926; P＜0.001. No adverse events occurred during the intervention period. On days 2 and 4 of the intervention, GCS scores were significantly higher in the experimental group than in the control group (P＜0.05), whereas no significant difference was observed in cough scores between the two groups (P＞0.05). Conclusion　The comprehensive chest physiotherapy program for postoperative ICU patients on mechanical ventilation constructed in this study is scientifically sound, feasible, and safe, and can shorten the duration of mechanical ventilation and length of ICU stay.