A novel thermo-sensitive poly(N-acryloyl alanine methyl ester) (PAAME) was synthesized by radical polymerization. The structures of the corresponding monomer and polymer have been confirmed by 1H NMR and FTIR measurements. The thermo-sensitivity of PAAME was investigated by measuring their lower critical solution temperatures (LCST) in pure water and at different pH solution. The results indicated that PAAME exhibited a reversible thermo-sensibility in its aqueous solutions at 17.7 °C. The drug release study showed that 72% caffeine was released from hydrogel at 37 °C after 6 hours, while more than 94% caffeine was gradually diffused into the medium at 18 °C.