We investigated the early microstructural alterations in hippocampus in MCI patients with cSVD by DKI. Our study found that MCI patients with cSVD show more seriously white matter hyperintensity, and showed significantly increased MD and RD values, and decreased MK, AK, RK, FA and KFA values in left hippocampus. In left hippocampus, values of FA, MK, RK, and KFA showed significantly positive correlations with MoCA score, while MD and RD values were negatively correlated with MoCA score. This may be due to the loss of neuron cell bodies, synapses and dendrites. DKI technique may be feasible to probe the microstructural changes of hippocampus in MCI patients with cSVD.