Impact modifier for polymethyl methacrylate resin having excellent impact strength and transparency and method of preparing the same

Disclosed is an impact modifier for polymethyl methacrylate resin having excellent impact strength and transparency and a method of preparing the same. The impact modifier for the polymethyl methacrylate resins is characterized by comprising a seed formed by polymerizing methyl methacrylate, a rubber core surrounding the seed, wherein the rubber core is formed by polymerizing a monomer mixture comprising alkyl acrylate, an aromatic vinyl compound, a cross-linkable monomer and a polyethylene glycol comonomer, and a shell surrounding the core wherein the shell is formed by polymerizing a mixture comprising methyl methacrylate and at least one compound selected from the group consisting of alkyl acrylate and an aromatic vinyl compound. The impact modifier improves impact strength without causing deterioration in transparency by using the polyethylene glycol comonomer in the process of producing the core.