Ibuprofen　was　encapsulated　into　pH-sensitive　hybrid　nanocomposite　using　amine-modified　bimodal　mesopores　silica　(BMMs)　as　core　and　poly(methylacrylic　acid)　(PMAA)　as　the　shell.　The　various　characterizations　showed　that　PMAA-coated　shell　played　a　pH-dependent　＂open-close＂　switch,　and　BMMs　as　a　stored　drug　carrier.　The　high　drug　loading　and　pH-responsive　release　performances　in　vitro　could　be　successfully　monitored　by　SAXS　techniques,　demonstrating　the　evolution　of　mass　fractal　with　surface　roughness　and　structural　irregularities.　The　release　mechanism　was　proposed,　showing　a　＂diffusion-controlled＂　profile　in　both　acidic　and　alkaline　medium.　Finally,　the　pharmacokinetics　of　released-IBU　in　mice　through　intravenous　injection　was　preliminarily　explored.