Thermo -responsive brush copolymers poly(methyl methacrylate(MMA)-co-2-(2-bromoisobutyryloxy)ethyl methacrylate (BIEM)-graft-(N-isopropyl- acrylamide)(NIPAAm) were synthesized using Cu-mediated "Iiving" radical polymerization (LRP) approach.The effect of grafting densities on their thermo-responsive phase transition behaviors in aqueous solution was investigated in detail. The lower critical solution temperature (LCST) of the brush copolymers can be adjusted as 35, 37 and 380C through the random, gradient and block backbone structure respectively. Their structure tunable thermo-responsive phase transition behaviors were further confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Furthermore, the temperature-responsive wettability of surfaces modified by the resulting brush copolymers made a contribution to the preparation of smart surface.