The influence of grafting density, the main chain polymerization degree and side chain length on polycarboxylate superplasticizer(PCE) cement paste fluidity for allyl polyoxyethylene ether acrylic acid(HPEG AA) was studied. The mathematical model of the PCE optimum molecular structure was established, and the effect of the ester group density on the properties of PCE was studied. Basing on the above conclusion, two kinds of PCE were designed and prepared using HPEG with relative molecular mass of 4000：PC R1 which released quickly and PC R2 which released slowly. The molecular structure of PCE was characterized. The molecular weight of PCE was determined by gel permeation chromatograph(GPC), and the functional groups of PCE were characterized by infrared spectroscopy(IR). The properties of the fresh concrete and hardened concrete with slow release PCE were determined, and the mathematical model and the design method was validated as well.