We synthesized the polymer brushes by conventional free radical polymerization and investigated the morphology evolution of block copolymer nanostructure on the brush treated surfaces. Our simple approach utilized a functionalized free radical initiator to add hydroxyl group to a chain end and an excess amount of a chain transfer agent to control the molecular weights of the brushes. The synthesized polymer brushes had narrow molecular weight distribution as well as hydroxyl end group and were successfully grafted onto silicon oxide layer by simple spin-coating and annealing process. The orientation of poly(styrene-block-methyl methacrylate)s (PS-b-PMMAs) coated on the brush grafted surface was finely controlled by the surface modification by polymer brushes.