The synthesis technology of water reducer containing polyethylene oxide (PEO) graft chains (PEO side chains), as well as sulfonic groups and carboxylic groups was discussed. The blended monomers consisted of acrylic acid and polyethylene glycol which was partially esterized with the overdosed acrylic acid. The reaction time and temperature of synthesis were selected according to the half life of initiator. The unit chemical structure of the polymer is proposed considering the molar ratio of comonomers. By testing the concentration of double bond in the residue and the cement paste fluidity, the synthesis conditions of the polycarboxylic type water reducer were determined.