The use of microwave technology is clean, efficient, targeted and so on. Microwave assisted synthesis and conventional oil bath were used to prepare methoxy polyethylene glycol methacrylate(MPEGMAA) by esterification of methacrylic acid(MAA) and methoxy polyethylene glycol(MPEG), and further polymerize into esters of polycarboxylate superplasticizer for performance analysis. The effects of acid and alcohol ratio, the amount of catalyst and the polymerization inhibitor, reaction time, esterification temperature and microwave power on the esterification ratio were studied by single factor method，and it was found that the optimal ratios and process solutions based on microwave assisted synthesis was n(MAA)∶n(MPEG)=5.0∶1.0. The amount of catalyst was 45% by the mass of MPEG. Amount of the polymerization inhibitor was 0.28% by the mass of MAA. Esterification temperature was 120℃. Reaction time was 100min and the microwave power was 1000W. Esterification ratio of the method was 9347%, which was 1.14 times that of conventional oil bath oil bath method. The reaction rate was 4.8 times that of the conventional oil bath method. Through the cement paste test, infrared spectrum analysis and rheological properties study, the microwave heating method is more conducive to the formation of esterification monomer ester bond. Dispersion and dispersion maintaining performance of synthetic esters of polycarboxylate superplasticizer are better.