 Diabetes mainly type II diabetes lead to the central nervous system CNS function impairment, especially the mild cognitive impairment MCI that increased the risk of progression to dementia. It was regarded that neurodegeneration contributes to the diabetic MCI, however, recent research suggested that CNS microvascular alterations are the mechanism for early diabetic MCI. But there still lacks an early warning system for the CNS micro-structure alterations during early diabetes. Latest neuroimaging techniques enable the measurement of brain blood flow, local neural activity,and the nuclei deposition of iron to reflect CNS micro-structure alterations. But these techniques are complicated and can not fully reflect the alterations with one single technique.We previous observed that 44.4 of diabetic patients demonstrate MCI and established the comprehensive protocols of measuring brain blood flow, local neural activity and the nuclei deposition of iron simultaneously based on the multimodal MRI technique so as to reflect the microstructure alterations reliably and validly. Therefore, we intend to integrate psychological measurement and clinical biochemical examination, and to establish the early warning system for the central nervous system micro-structure alterations during early diabetes based on the multi-modal MRI technique. The reliability and validity of this system will be tested in the diabetic rat model. The early warning system will likely assist in screening patients with diabetic microstructure alterations, to perform early intervention so as to prevent or delay the progression from diabetic MCI to dementia. 