本发明公开了一种新型聚羧酸系减水剂的制备方法,采用如下步骤制备:1)不饱和酸小单体,胺类不饱和小单体在链转移剂,引发剂,还原剂作用下进行反应得到含胺基共聚产物;2)聚乙二醇单甲醚中滴加入过量的二异氰酸酯中,在催化剂的作用下反应得到聚乙二醇单甲醚单异氰酸酯;3)将得到的含胺基共聚产物加入聚乙二醇单甲醚单异氰酸酯反应 The invention discloses a preparation method of a novel polycarboxylate superplasticizer, which is prepared by the following steps: 1) the action of the unsaturated acid small monomer, the amine unsaturated small monomer in the chain transfer agent, the initiator and the reducing agent 2) polyethylene glycol monomethyl ether was added dropwise to an excess of diisocyanate, under the action of the catalyst to give polyethylene glycol monomethyl ether monoisocyanate; 3) The resulting The amine-containing copolymerization product is reacted with polyethylene glycol monomethyl ether monoisocyanate