Objective To study the effect of mindfulness decompression therapy combined with respiratory exercise therapy on postoperative perceived stress,anxiety and depression in patients with lung cancer.Methods A total of 100 lung cancer patients treated in Coast Guard Hospital of Chinese People′s Armed Police Force from January to December 2021 were selected as the research objects and divided into control group and observation group by random number table method, with 50 cases in each group. Patients in the control group received routine nursing intervention, while patients in the observation group received mindfulness-based stress reduction therapy combined with respiratory exercise therapy on the basis of the control group. The scores of self-rating anxiety scale (SAS), self-rating depression scale(SDS), the Chinese version of perceived stress scale (CPSS), the cancer fatigue scale (CFS), strategies used by people to promote health (SUPPH), pulmonary function indexes (forced expiratory volume in one second [FEV1], forced vital capacity [FVC], FEV1/FVC), and 6-min walk test (6MWT) were compared between the two groups. Results The scores of SAS, SDS, CPSS and CFS in the observation group at 8 weeks after operation were lower than those in the control group, and the differences were statistically significant (P＜0.05). The SUPPH score, FEV1, FVC, FEV1/FVC and 6MWT of the observation group were higher than those of the control group at 8 weeks after operation, and the differences were statistically significant (P＜0.05). Conclusion The implementation of mindfulness decompression therapy combined with respiratory exercise therapy in patients with lung cancer can help to improve their anxiety and depression, cancer-related fatigue and perceived stress level, improve self-efficacy, lung function and exercise endurance.