Tourette syndrome (TS) is a childhood-onset neurobehavioral disorder characterized by the presence of multiple motor and vocal tics. The motor tics usually begin between the ages of 3-8 years, with the worst tic severity for most patients falls between age 7-15 year. Often tics are accompanied by comorbidities such as obsessive-compulsive disorder (OCD), attention-deficit-hyperactivity disorder (ADHD) or other social and behavioral disturbances.To date, the neural basis of TS is not fully understood yet. It was generally proposed by researches that TS arose from cortico-striato-thalamo-cortical(CSTC) circuit disturbances. Over the past decade, it has become clear that white matter (WM) plays a critical role in nearly every aspect of cognitive development, healthy cognitive function and cognitive decline in aging. Moreover, many psychiatric disorders-from autism to schizophrenia-are associated with white-matter abnormalities. White-matter tissue properties change over the lifespan and models of the biological principles underlying these changes are critical for diagnosing abnormalities in the living human brain. To our knowledge, this is the first study that used both Tract-Based Spatial Statistics (TBSS) and Atlas-based approach to analyze Diffusion tensor imaging (DTI) data of TS children.To investigate the microstructural changes of the white matter involved in children with Tourette syndrome (TS) by Diffusion tensor imaging (DTI).We investigated microstructural changes of white matter(WM) using DTI, and correlated these changes with tic severity and duration. DTI from 27 TS children (age at imaging, 9.00±3.374 years, age range: 3–16 years; 20 males) were compared with 27 age and gender matched health control（HC） children using a 3.0T Philips scanner. Using Tract-BasedSpatial Statistics (TBSS) and Atlas-based approach, we characterized altered brain microstructure of white matter in these 27 TS children. All of the 27 TS children met the DSM-IV-TR criteria. With DTI, microstructural changes could be quantified by TBSS and Atlas-based ROI analysis. TBSS analyses revealed significantly reduced fractional anisotropy (FA) in multiple white matter skeleton clusters of the patients, including body of right corticospinal tract, corpus callosum, forceps major, left and right superior longitudinal fasciculus, left anterior thalamic radiation, right inferior fronto-occipital fasciculus(Figure1). Significantly increased RD could be found in left inferior fronto-occipital fasciculus and contralateral superior longitudinal fasciculus（SLF）. Atlas-based ROI analysis was performed both in WM tracts as well as in basal ganglia and thalamus. For WM tracts, FA-decrease in left superior longitudinal fasciculus in combination with increased radial diffusivity (RD) and mean diffusivity (MD). FA and axial diffusivity (AD) were both decreased significantly in bilateral anterior limb of internal capsule（ALIC）. Atlats-based ROI analysis also shows a decrease of FA and increase in radial diffusivity(RD) in bilateral cingulum bundle projecting to the cingulate gyrus（CGC） and inferior fronto-occipital fasciculus（IFO）. There are wide spread changes (reduced FA) in forceps minor, right corona radiata, superior fronto-occipital fasciculus, left anterior thalamic radiation and bilateral external capsule. Axial diffusivity (AD) was decreased significantly in right posterior thalamic radiation and posterior corona radiate. For basal ganglia and thalamus, we found FA was decreased in left and right Putamen, and left thalamus. For WM tract, FA value in left anterior limb of internal capsule, right anterior corona radiata（ACR） ,left external capsule（EC）, left superior longitudinal fasciculus, left superior fronto-occipital fasciculus（SFO） were significantly negatively correlated with YGTSS scores of the patient group,RD and MD value in left superior longitudinal fasciculus（SLF） were significantly positively correlated with YGTSS scores of the patient group. For basal ganglia and thalamus, only FA value in left thalamus were significantly negatively correlated with YGTSS scores.FA/AD decrease and RD/MD increase in white matter tracts in CSTC as well as basalganglia and thalamus were found. The positive relation between higher RD, MD and more tics and the negative correlation between higher regional FA values and fewer tics, suggests that these alterations of white matter microstructure represent adaptive reorganization of somatosensory and motor processing in TS. We interpret the symptom severity related white matter with not only altered interhemispheric connectivity but also long association fibre bundles within one hemisphere as evidence of ongoing structural plasticity.