Objective To investigate the characteristics of brain MRI in the patients with maple syrup urine disease(MSUD). Methods Nine patients with MSUD were diagnosed by gas chromatography mass spectrometry,tandem mass spectrometry and gene test.The MRI,clinical featuresand laboratory tests were analyzed.Results The 9 patients onset age were 3 days to 6 years old.The symptoms were varied such as poor response,lethargy,seizures and learning difficulties.Remarkable elevations of blood levels of leucine and valine were found in all patients.All patients had MRI examination,2 of them also took the examination of proton magnetic resonance spectroscopy (1 H-MRS).Involving cerebellar hemisphere,cerebellar peduncle,cerebral peduncle,brain stem,globus pallidus in 5 cases respectively,thalamus and posterior limb of internal capsule in 4 cases,centrum semiovale in 3 cases.2 cases also showed abnormal signal in corpus callosum,occipital,deep temporal lobe,and frontal lobe,parietal lobe.All lesions showed mild low signal intensity in T1 ,mild high signal intensity in T2 and obvious high signal intensity in DWI,except one case.1 H-MRS did not show a methyl resonance peak at 0.9 ppm in the two patients.Conclusion The MSUD lacked of specific clinical features.The MRI characteristics are the myelinated white matter such as the cerebellar hemispheres,posterior limb of the internal capsule,the brainstem,cerebellar peduncle,cerebral peduncle showing high signal in DWI.