Objective To study the efficacy of retroauricular subperiosteal injection of methylprednisolone for the treatment of sudden deafness and persistent tinnitus complicated with metabolic syndrome and its effect on blood glucose, blood pressure and triglyceride levels, so as to explore the effective treatment method.Methods Sixty-six patients with sudden deafness and persistent tinnitus complicated with metabolic syndrome were randomly and equally divided into experimental group and control group. Both groups were treated for 15 days. Patients in the experimental group were given retroauricular injection of 0.5 mL methylprednisolone and 0.3 mL lidocaine, supplemented by intravenous injection of ginkgo biloba extract and oral administration of mecobalamine tablets, as well as health education and psychological counseling. The patients in the control group received intravenous injection of methylprednisolone, and the remaining treatments were the same as the experimental group. All patients were followed up for more than 3 months. The differences of hearing recovery, tinnitus severity, blood glucose, blood pressure and triglyceride fluctuation between the two groups were compared.Results ①The total effective rate of pure tone hearing after treatment in the experimental group was 87.88%, which was higher than that in the control group (54.55%). Their total effective rates 3 months after treatment were 93.94% and 60.61%, respectively. The differences were both statistically significant (P<0.05). The effective rate of tinnitus in the experimental group (78.79%) was higher than that in the control group (42.42%), and the difference was statistically significant (P<0.05). ② There were no significant differences in blood glucose, blood pressure and triglyceride indexes in the experimental group before and after treatment, suggesting that this treatment regimen could ensure effectiveness and safety with local injection of glucocorticoid and avoid systemic adverse reactions caused by intravenous adminstration.Conclusion With advantages of satisfactory efficacy, simple operation, high acceptance of patients as well as slight toxic and side effects, the retroauricular injection of methylprednisolone should be popularized in clinical application for the treatment of sudden deafness and persistent tinnitus patients with metabolic syndrome.