NOVELTY - Poly carboxylic acid concrete superplasticizer comprises poly carboxylic multipolymer containing carboxyl, sulfonates and side chain of polyoxyethylene.    USE - The poly carboxylic acid concrete superplasticizer is useful for crucial component of high performance concrete, sea project concrete, nuclear power plantation concrete and anti-corruption concrete and being widely used in industrial and civil construction, water conservancy, road, traffic and nuclear project field. The process is also useful for synthesizing poly carboxylic acid concrete superplasticizer (claimed).    ADVANTAGE - The poly carboxylic acid concrete superplasticizer has high water reducing ratio, low chlorine and alkali, when 0.7-1.2 wt.% gelled material is added in, the cement mixture is high of flowing performance, benign of workability and able to effectively control slump loss. The process is simple, easy to control reaction condition, environmental friendly and of reasonable cost    DETAILED DESCRIPTION - Poly carboxylic acid concrete superplasticizer of structural formula (CH2-CCH3COO(CH2CH2OCH3)n)a-(CH2-CCH3COONa)b-(CH2-CHCH2SO3Na)c-(CH2CH3COO(CH2CH2OCH3)nCH2)d comprises poly carboxylic multipolymer containing carboxyl, sulfonates and side chain of polyoxyethylene. An INDEPENDENT CLAIM is included for the synthesizing method for poly carboxylic acid concrete superplasticizer comprises (a) using methacrylic acid monomer and poly ethylene glycol as raw material, proportionally adding oil of vitriol or triphenylsulfonium tosylate or both as catalyzer, adding a small amount of p-hydroquinone anti coagulant, control temperature is 110-140 degrees C, stir the mixture to carry on esterification for greater than or equal to 3 hours, and obtaining macromonomer of methoxypolyethylene glycol methacrylate (MPEGMA) after reacting; and (b) adding methacrylic acid or methyl allyl sodium sulfonates in macromonomer of MPEGMA obtained in (a), use ammonium persulphate or sodium persulfate as initiator and mercaptoethanol as chain-transferring agent, carrying on copolymerization in aqueous solution under 85 plus minus 5 degrees C, when copolymerization is over, and use sodium hydroxide to neutralize aqueous solution until pH value reaches 6.5 plus minus 0.5, and then obtaining 25 wt.% poly carboxylic acid concrete superplasticizer.