Objective: To investigate the effects of motivational interview education on psychological status, compliance behavior and quality of life in patients with malignant tumors combined with diabetes mellitus. Methods: This is a retrospective study. Eighty patients with malignant tumors combined with diabetes mellitus admitted at The Fourth Hospital of Hebei Medical University from January 2021 to June 2022 were included as subjects and divided into observation group and control group according to the intervention measures. Patients in the control group were given routine health education intervention, while those in the observation group were given motivational interviewing intervention on the basis of the control group. We compared the prognosis, cognitive function, quality of life, relief of cancer pain before intervention and three months after the intervention of the two groups were compared. Results: At three months after the intervention, the total remission rate of cancer pain in the observation group was higher than that in the control group (p<0.05), while the levels of FBG and 2hPG in the observation group were significantly lower than those in the control group (p<0.05). Self-Rating Anxiety Scale (SAS) and Self-rating depression scale (SDS) scores decreased in both groups three months after the intervention, with the level of reduction in the observation group being higher than that in the control group (p<0.05). The overall compliance was higher in the observation group than in the control group (p<0.05). Conclusion: Motivational interviewing leads to alleviate negative emotions, improve the psychological status, enhance compliance behavior and improve quality of life in patients with malignant tumors combined with diabetes mellitus.