This paper aimed to determine whether the brain structure of the people who practice long-term Tai Chi exercises differs from that of their sedentary counterparts,and whether the difference is associated with exercise duration and skill level.Diffusion tensor imaging and whole-brain voxel-based analysis(VBA)were used in this study.The volunteer-participants were 20 older Tai Chi practitioners and 25 age-,gender-,health-,and fitness condition-matched sedentary people.The mean exercise duration of the Tai Chi group was 8.45 years.A medical examination confirmed that all of the participants were qualified to undergo MRI scanning.The imaging graphs were processed using whole-brain VBA to identify differences in brain volume.The volumes of interest were analyzed further to determine the between-group differences in isotropic fraction(FA)and apparent diffusion coefficient(ADC).The rank correlation analysis was performed for FA and ADC according to the exercise duration and skill level.Results of the VBA analysis indicated that the exercise group had higher FA in splenium corporis callosi(0.86 0.04 vs.0.84 0.02,P < 0.05)and higher ADC value(0.78 0.05 vs.0.74 0.05,P < 0.05)than the control group.In the exercise group,the FA value of splenium of corpus callosum was moderately related to the exercise duration(r = 0.45, p = 0.045),but highly related to the skill level(r = 0.699,p < 0.01).We concluded that Tai Chi exercise could change the cerebral white matter fiber,which had a correlation with the exercise duration and skill level.Therefore,the long-term and skillful exercise of Tai Chi would delay the brain volume atrophy,which could be the central basis for the improved balance capacity of Tai Chi practitioners.