O-GlcNAcylation is an abundant, essential and dynamic protein post-translational modification of cytosoic proteins in metazoans and can compete with phosphorylation at similar Ser/Thr sites of target proteins 1.The enzyme of O-GlcNAc metabolism (OGT/OGA) are enriched in the brain and many proteins important for neuronal function are modified by O-GicNAe including microtubule-associated protein tau, β-amyloid precursor protein (AP), clathrin-assembly proteins and neurofilaments.Pathological hyperphosphorylation of tau is characteristic of Alzheimers disease (AD) and the associated tauopathies.So a potent and specific O-GlcNAcase inhibitor can be used to enhance O-GlcNAc level and downregulate phophorylaiton oftau and further provide a new drug for AD therapy 2.we found a potent and competitive inhibitor (compound 7) of human O-GlcNAcase (OGA) by Biological screening, and it displayed 28-fold selectivity over human lysosomal β-hexosaminidase A.In addition, cell-based assay revealed that this compoud was cell-permeant and effectively induced cellular hyper-O-GlcNAcylation at 10 μM concentration.