The　pH-responsive　hollow　poly(acrylic　acid)　(HPAA)　microspheres　with　regulated　cavity　structure　and　various　shell　thicknesses　were　synthesized.　Their　structural　parameters　and　textural　properties　were　characterized　by　various　techniques.　The　ibuprofen　loading　results　indicate　the　good　drug　loading　capabilities　of　HPAA　microspheres　from　13.81　to　17.18%.　Their　ibuprofen　release　properties　demonstrated　their　good　pH　sensitivity　and　distance-controlled　drug　diffusion　process.　Specially,　the　small-angle　X-ray　scattering　technique　was　used　to　suggest　the　surface　roughness　and　structural　irregularities　of　HPAA　before　and　after　drug　loading　and　releasing.　These　findings　clearly　indicate　the　potential　of　HPAA　microspheres　to　be　used　as　promising　candidates　in　drug　delivery.　[GRAPHICS]　.