Abstract: A phenol product was synthesized with 4-cumylphenol and styrene as raw materials, acid catalyst as catalyst, and a prepolymer was produced by the reaction of PEG-6000 wih TDI, then the phenol product was reacted with the prepolymer to synthesize the aqueous polymeric dispersant. The synthesized product was characterized by FTIR, MS and GPC， and the surface tension of its solution was measured by surface tensiometer.The condition of synthesizing the dispersant was examined. Tt was found that the polymeric dispersant with the suitable molecular weight could be produced when the mole ratio of -NCO: -OH was 3:1.