Objective:To explore the effects of rehabilitation intervention based on health behavior change theory on mental resili-ence and sleep quality of patients with gastric cancer undergoing chemotherapy.Methods:A total of 160 patients with gastric cancer treated by chemotherapy in the First Affiliated Hospital of Xiamen University from June 2022 to June 2023 were divided in-to the observation group and the control group according to the random number table method,with 80 patients in each group.The patients in the control group received conventional rehabilitation nursing while the patients in the observation group received reha-bilitation intervention based on the theory of health behavior change.The improvement of mental resilience,sleep quality and qual-ity of life scores of patients with gastric cancer before and after chemotherapy were compared between the two groups.Results:The psychological resilience level,sleep quality level and quality of life score of gastric cancer patients in observation group were sig-nificantly better than those in control group(P<0.05).Conclusion:Rehabilitation intervention based on the theory of health be-havior change can effectively improve the mental resilience and sleep quality of patients with gastric cancer.