N-isopropylacrylamide　(NIPAAm)　was　used　to　synthesize　NIPAAm　homopolymer　(nonionized)　and　NIPAAm-sodium　methacrylate　copolymer　(ionized).　The　swelling　equilibria　for　both　gels　were　obtained　in　aqueous　solution　of　ethanol　with　concentration　ranging　from　0　to　100%(by　mass)　at　25degreesC.　The　swollen　gel　in　water　shrank　first　with　the　addition　of　a　small　amount　of　ethanol　and　then　reswelled　with　further　addition　of　ethanol　showing　not　only　a　discontinuous　volume　phase　transition　but　also　a　typical　reentrant　phenomenon.　A　thermodynamic　model　based　on　the　UNIQUAC　with　the　＂free-volume＂　contribution　was　applied　to　correlate　and　predict　the　swelling　behavior　of　the　poly(NIPAAM)-gels　in　ethanol-water　mixture.