Objective To explore the effects of mindfulness training on posttraumatic growth and quality of life in lung adenocarcinoma patients. Methods A total of 80 patients with lung adenocarcinoma in 2 units of respiratory department were divided into a control group (40 cases) and an intervention group (40 cases) using cluster randomization method. The control group received routine care for cancer patients in respiratory department, while the intervention group additionally received mindfulness training for 8 times. The two groups were investigated using the Chinese-Posttraumatic Growth Inventory (C-PTGI) and the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (QLQ-C30) before and after the intervention. Results Thirty-eight patients in the control group and thirty-three patients in the intervention group completed the study． After the intervention, the total score of C-PTGI and its subscale scores of life experience，personal power，new possibilities, self-change in the intervention group were significantly higher than those in the control group (all P<0.05), the total score of QLQ-C30 and its dimension scores of role function,emotional function, cognitive function, social function in the intervention group were significantly higher than those in the control group (all P<0.05). Conclusion Mindfulness training can significantly improve the level of post-traumatic growth level and the quality of life of lung adenocarcinoma patients.