Thermo- and pH-responsive polyrotaxane (PR)-based triblock copolymers were synthesized by atom transfer radical polymerization (ATRP) of N-isopropylacrylamide initiated with polypsudorotaxanes which were presynthesized from bromine end-capped poly(ethylene glycol)/poly(propylene glycol) with cyclodextrins in the presence of CuBr/HMDETA under near physiological conditions. The triblock copolymers were characterized by(1)H NMR, FT-IR, GPC (gel permeation chromatography) analyses. Thermo- and pH-responsive behavior evaluated by UV-Vis spectroscopies, DLS (dynamic light scattering), and TEM (transmission electron microscopy) images showed that its lower critical solution temperature (LCST) was slightly increased with increasing pH values due to hydroxyl groups of cyclodextrin depending on pH values.