The present invention relates to a method of preparing a super absorbent polymer (SAP). The preparation method for SAP according to the present invention includes: preparing a first polymer by carrying out a thermal polymerization or photo polymerization of a monomer composition comprising a water-soluble ethylene-based unsaturated monomer and a polymerization initiator； preparing a second polymer by carrying out a thermal polymerization or photo polymerization of a monomer composition comprising a water-soluble ethylene-based unsaturated monomer and a polymerization initiator； drying the first polymer； milling the dried first polymer； and mixing the milled first polymer with the second polymer in the free swelling state using the crosslinking solution to cause a crosslinking reaction of the first and second polymers. According to the present invention, it is possible to obtain a super absorbent polymer (SAP) having high centrifuge retention capacity and high absorption under pressure.
