Objective To investigate how tailored nursing care and mental health treatment can improve the quality of life for senior diabetic patients. Methods From April 2021 through April 2022, one hundred of our senior diabetic patients who came to our hospital were randomly chosen to participate in this study. Two groups of fifty were selected at random to serve as the control and observation groups. Normal nursing care was provided to the control group, whereas the observation group received tailored treatment in addition to cognitive therapy based on the results. Over the course of six months, both groups received intervention. Glycated haemoglobin (HbA1c), fasting blood glucose (FBG), and two-hour postprandial glucose (PBG); Health survey summary table (SF-36) score, hamilton anxiety scale (HAMA), hamilton depression scale (HAMD), and compliance were among the measures used to evaluate the two groups. Results Fasting blood glucose, 2-hour postprandial glucose, and haemoglobin A1c all decreased significantly in both groups after the intervention; however, all three markers dropped more in the observation group than in the control group; The SF-36 scores improved significantly after intervention for both groups; however, the SF-36 scores of the observation group were significantly higher than those of the control group (P<0.05). The HAMA and HAMD scores of the post-intervention groups were both significantly lower than the pre-intervention levels, with the scores of the observation group being significantly lower than those of the control group; After the interventions were implemented, both groups showed notable improvements in compliance compared to before, with the observation group showing considerably better compliance than the control group (P<0.05). Conclusion A high clinical reference value is associated with the fact that glycemic control, quality of life, psychological state, and compliance are all enhanced when older patients with diabetes receive individualised nursing care that also incorporates mental intervention.