Abstract： Objective To investigate the influence of psychological treatment and diet therapy on diabetes mellitus.Methods Sixty-eight cases of diabetes mellitus were randomly divided into two groups.The observation group was treated with psychological treatment and diet therapy. Meanwhile the control group was treated with routine therapy.Results The laboratory findings were compared wthin the two groups(P<0.05).Neurotic and psychological symptoms and general health in observation group were more improved than control group (P<0.05).Conclusion Psychological treatment combined with diet therapy is effective in treatment of diabetes mellitus and it is helpful to extend and improve the lives of patients.