Surface modification with polymer is widely applied to various kinds of applications. Recently, polymer brushes, which is a layer of polymers attached with one end to a surface, have attracted much attention as functionalized surfaces. In particular, ionic polymer brushes provide ultra-low friction or anti-fouling because they act as highly hydrated soft film. Almost ionic polymer brushes have been prepared from synthetic polymers. Few biopolymers have been investigated for polymer brush studies. DNA which is one of ionic biopolymers has unique functions and conformations which synthetic polymers don’t have. We found that cationic gold nanorods (30 x 10 nm) were adsorbed to DNA bush (148 bp) prepared on a glass surface in an aqueous solution by observation using extinction spectra. When the cationic charge density of gold nanorods were decreased, nanorods were immobilized perpendicularly to the substrate by binding to DNA elongated. This indicates that self-assembled alignment of gold nanorods can be achieved by using DNA brush. Formed aligned gold nanorods can be used for plasmonic color analysis.