The present invention relates to an acrylic processing aid, a method for preparing the same, and a polyvinyl chloride resin composition comprising the same. More specifically, the present invention relates to an acrylic processing aid having a core-shell structure comprising the core and shell comprise a polymer prepared by copolymerizing a methyl methacrylate monomer and an alkyl acrylate monomer having 1 to 18 carbon atoms, and wherein the core comprises the polymer having a weight-average molecular weight ranging from 10,000,000 to 18,000,000 g/mol, a method for preparing the same, and a polyvinyl chloride resin composition comprising the same.