A polycarboxylate type superplasticizer (PC) was synthesized by water solution polymerization using itaconic acid polyethylene glycol ester (IAPEG), acrylic acid (AA), maleic anhydride (MA) and sodium methylacryl sulfonate (MAS) as monomers and ammonium persulfate as initiator. The structure of copolymer was characterized by FT-IR. The molecular weight and the distribution of copolymer was characterized by GPC. And the influence of reaction condition on properties of polycarboxylate type superplasticizer were discussed. The results showed that the optimal reaction conditions are as follows: the molar ratio of IAPEG to MA to AA to MAS is 1.5:4:6:3, the dosage of initiator is 10 % according to the mass of all monomers, the reaction temperature is 80℃, the reaction time is 5h. The polycarboxylate type superplasticizer synthesized under the optimum conditions can reduce the surface tension of the solution, promote the dispersion of cement particles and make the fluidity of cement paste better. The water reducing ratio of concrete is 39.2%, The compressive strength ratio of the concrete can reach 191.4%at 7d and 154.7%at 28d respectively.