Quadripolymer AMPF was synthesized with sulfanilic acid（C6H7NO3S）, p-methyl benzenesulfonic acid（C7H8O3S）, phenol（C6H6O） and formaldehyde（CH2O）. By taking the single factor analysis method , the optimal pH synthesis condition of product is 9;molar ratio of monomer n（C6H7NO3S）：n（C7H8O3S）：n（C6H6O）：n（CH2O）is 1:4:6:13.2; the reaction temperature is 75 ℃. Meanwhile, the structure of this reducer is clarified though infra-red spectrum, 1H—NMR spectrum and the results show that the molecular structure of artificial synthesis product is in accord with ideal one. The thermogravimetric experiment indicates good thermal stability of this reducer. Moreover, this polymer has been demonstrated with good temperature resistance, salt tolerance and excellent compatibility.