The　loading　properties　of　ibuprofen　(IBU)　were　investigated　using　poly(N-isopropylacrylamide-co-acrylic　acid)　P(NIPAM-co-AA)　copolymer　nanoparticles　as　a　carrier.　Subsequently,　the　sensitivity　of　controlled　release　performance　during　changing　external　conditions　and　composition　of　copolymer　were　evaluated　in　detail.　The　results　showed　that　the　introduction　of　AA　chains　into　PNIPAM　framework　enhanced　the　loading　of　IBU　and　the　maximum　loading　capability　of　P(NIPAM-co-AA)-3　reached　up　to　7.9　wt%.　The　release　behaviors　of　IBU-loaded　copolymers　exhibited　high　responsiveness　to　temperature　and　pH　values.　For　example,　P(NIPAM-co-AA)-10　exhibited　a　high　cumulative　release　amount　of　83.2%　at　37　A　degrees　C/pH　7.4,　and　a　significant　decrease　in　the　release　amount　of　32.2%　at　37　A　degrees　C/pH　2.0.　The　influence　of　various　amounts　of　acrylic　acid　(AA)　and　salt　effect　(ionic　strength)　on　the　swelling　behaviors　were　demonstrated　via　dynamic　light　scattering　method.　Their　microstructures　and　morphologies　were　characterized　using　scanning　electron　microscopy　(SEM),　transmission　electron　microscopy　(TEM)　and　small-angle　X-ray　scattering　(SAXS)　techniques,　which　confirmed　the　presence　of　fractal　structures　with　D-m　(2.65-2.87)　or　D-s　(2.0-2.33).　These　results　further　suggested　that　the　structural　evolution　of　P(NIPAM-co-AA)　copolymer　with　increasing　AA　content　had　occurred　from　loose　networks　to　dense　aggregates　with　statistical　self-similarity.　The　IBU-release　mechanism　was　proposed,　whereas　the　IBU　diffusion　contribution　from　P(NIPAM-co-AA)　was　thoroughly　elucidated　using　three　empirical　equations,　namely　Korsmeyer-Peppas　model,　modified　Korsmeyer-Peppas　model　and　Higuchi　model,　respectively.　The　obtained　results　demonstrated　that　the　release　procedure　of　P(NIPAM-co-AA)　was　driven　by　typical　non-Fickian　diffusion　mechanism　in　the　basic　medium,　while　in　acid　medium　a　two-stage　release　mechanism　was　observed　due　to　their　aggregation　behaviors.