Objective: To conduct an in-depth analysis of the effectiveness and value of applying a nursing plan for respiratory function training based on self-efficacy theory in patients after radical resection of lung cancer. Methods: The study subjects were patients undergoing radical resection of lung cancer, all of whom were sourced from our hospital. A total of 60 patients were included, with the time frame spanning from January 2024 to December 2025. Using a random number table method, all patients were divided into a control group and an observation group (n = 30). The control group received conventional nursing care, while the observation group received respiratory function training nursing care based on self-efficacy theory. Relevant indicators were quantified for both groups. Results: After nursing care, the observation group showed significant improvements in pulmonary function indicators, blood gas indicators, as well as inflammatory factor and oxidative stress indicators, which were superior to those of the control group (p < 0.05). Conclusion: For patients after radical resection of lung cancer, the nursing care plan for respiratory function training based on self-efficacy theory has yielded remarkable results, improving indicators such as pulmonary function and blood gas. It is worthy of promotion and application.