The invention discloses a preparation method and application of a high-density RGD peptide modified material. The preparation method comprises the following steps: dispersing a material, modified in the way that the surface is provided with an active group, into methylbenzene, adding a catalytic amount of 4-dimethylamino-pyridine, and slowly dropwise adding triethylamine and 2-bromoisobutyryl bromide under ice-bath, so as to prepare an initiator; adding cuprous bromide, 2,2'-dipyridyl and poly(ethylene glycol) methyl ether methacrylate into the initiator, so as to obtain a macromolecular polymer; adding the macromolecular polymer into a dimethylformamide solution containing an activating agent and 4-dimethylamino-pyridine to obtain an activated polymer brush, and adding RGD peptide for performing reaction in the dark at the room temperature for 18 hours; transferring a cell into the RGD peptide modified polymer brush, and performing reaction on a shaking table at the temperature of 4 DEG C for 20 minutes by adopting a phosphate buffer solution as a suspension liquid, so as to obtain the high-density RGD peptide modified material. The method is moderate in reaction conditions, simple, convenient and feasible in procedures, and achieves the purpose of fixing a cell on the surface of a solid material with high concentration and high density.