A double-hydrophilic diblock copolymer of poly(N-isopropyl acrylamide) -b-poly(N,N-dimethylamino-2-ethyl methacrylate) (PNIPAm-b-PDMAEMA) with well-defined structure and narrow molecular weight distribution (Mw/Mn = 1.27) was synthesized via reversible addition - fragmentation chain transfer (RAFT) polymerization using S-1-dodecyl-S’-(α,α’-dimethyl-α’’-acetic acid) trithiocarbonate (DDATC) and 2,2-azobisisobutyronitrile (AIBN) as chain transfer agent and initiator, respectively. The PNIPAm-b-PDMAEMA was characterized with FT-IR, 1H-NMR and gel permeation chromatography (GPC). The pH and temperature induced micellization of PNIPAm-b-PDMAEMA in the aqueous solution was investigated by transmittance measurement, fluorescence spectroscopy, potentiometric titration and dynamic light scattering (DLS). The copolymer exhibits temperature-responsive micellization in aqueous solution with a lower critical solution temperature (LCST) of 32.3 oC. As raising the temperature over LCST, the PNIPAm block turned to hydrophobic which caused formation of the global micelle composed of PNIPAm core and PDMAEMA shell. The hydrodynamic radius Rh of the micelle measured with DLS about 50 nm and increased with increasing temperautre. The Rh of the micelles increased with increasing temperature. The copolymer exhibits pH-sensitive associate behavior in aqueous solution and the threshold pH value of the pH-induced micellization is about 9.8 at 25 oC. The Rh of the micelle composed of PDMAEMA core and PNIPAm shell is about 31 nm at pH 11.0.