The invention relates to an organic-inorganic hybrid silica modified acrylic resin and a coating thereof. The organic-inorganic hybrid silica modified acrylic resin comprises, by weight, 8-14 parts of propylene glycol mono-n-butyl ether, 12-18 parts of diethylene glycol monobutyl ether, 10-12 parts of vinyl group-containing active silica, 9-11 parts of acrylic acid, 8-12 parts of hydroxypropyl methacrylate, 10-12 parts of methyl methacrylate, 17-19 parts of n-butyl acrylate, 5-7 parts of tert-butyl hydroperoxide and 7-9 parts of ethylene glycol monobutyl ether. The coating is suitable for anticorrosion of metal workpieces; and the final hardness of a coating layer obtained by using the coating reaches 2H, the impact strength is 50Kg.cm, the adhesion is 0 grade, the coating layer has very excellent corrosion resistance, the salt spray resistance reaches 1000h, the unidirectional corrosion width is not greater than 2mm, the coating layer has good weatherability, and a result of 1000h QUV ageing test shows that the light loss rate is not greater than 10%, and delta E is not greater than 1.0.