Brain development in the first few years of life is dramatic. The microstructural changes of infant grey matter measured by mean kurtosis, a non-Gaussian diffusion metric more sensitive to cortical microstructure than traditional diffusion metric, is not known. This study recruited 16 typical developing 3-32-months-old infants to investigate microstructural changes of the cerebral cortex by using Diffusion Kurtosis Imaging (DKI). Our results showed positive correlation between the mean kurtosis (MK) value and age. Differentiated age-dependent MK increases among different cortical regions suggest spatiotemporally heterogeneous pattern in cortical development.