It is reported that OSAS may cause cognitive function disorder of children due to chronic hypoxia for a long time［1］. However, it is not clear whether there are any structural changes of cerebral regions, e.g. white matter (WM). Diffusion kurtosis imaging is now widely used in the detection of cortical structural changes across kinds of diseases. In the present study, DKI is used to investigate microstructural changes of WM in OSAS children compared with normal healthy controls.