We　presented　a　facile　method　to　prepare　uniform　size　and　stable　property　graphene　quantum　dots　(GQDs)　from　chemical　cutting　the　double-walled　carbon　nanotube　with　blue　light　emission　in　a　chlorobenzene　solution.　The　double-walled　carbon　nanotube　was　firstly　cut　into　graphene　nano　sheets　(GNSs)　in　acidic　in　the　condition　of　heating　and　stirring,　then　chlorobenzene　was　used　to　separate　GQDs　from　GNSs　in　water.　The　chlorobenzene　solvent　enabled　the　preparation　of　GQD-PVK　hybrid　nanocomposite.　Nonvolatile　rewritable　memory　effect　was　observed　for　the　GQD-based　nanocomposite,　suggesting　the　promising　applications　of　GQDs　in　data　storage.　Moreover,　due　to　the　easy　solution　process,　we　demonstrated　the　design　and　realization　of　flexible　GQD-based　memory　device.　The　memory　has　performance　as　follow:　low　driving-voltage,　high　ON/OFF　ratio,　high　cycles,　high　repeatability　and　stability.　This　work　may　expand　the　application　of　GQDs　to　the　portable　electronic　devices.