The present invention relates to an acryl-silicon rubber complex polymer which has a seed-core-shell structure wherein vinyl monomer and hydrophilic monomer are cross-linked on the seed; the acryl-silicon complex IPN core having an IPN (interpenetrating network) structure formed by radical polymerization of acryl monomer and hydrosilyation of silicon rubber in which silicon rubber particles are dispersed by being cross-linked to acryl rubber, in a continuous phase, is formed on the seed; and a shell prepared by graft-polymerization of C.sub.1-C.sub.4 alkyl methacrylate to the acryl-silicon complex IPN core is formed on the core, and a method of preparation and use of the same, thereby having excellent impact resistance, weatherability and gloss, so that it can be effectively used as an impact modifier for vinyl chloride resin.