本发明提供一种聚酯超分散剂及其制备，以及一种异氰酸酯的制备方法。本发明提供的聚酯超分散剂，具有如下结构式(I):其中，式(I)中的R为二异氰酸酯脱去‑NCO的残基或多聚异氰酸酯脱去‑NCO的残基；R为单端羟基聚环氧乙烷脱去端羟基的残基；R为脱去‑NH的氨基酸残基，所述氨基酸具有至少一个含‑COOH的链段和至少一个含‑NH的链段；式(I)中，0＜m≤9，0＜n≤9。在制备异氰酸酯的成盐工序中引入本发明的聚酯超分散剂，可以避免结块现象的发生，增加二胺盐酸盐溶液的流动性，提高生产效率。

The invention provides a polyester hyperdispersant and preparation thereof as well as a preparation method of isocyanate. The polyester hyperdispersant provided by the invention has the following structural formula (I): (the formula (I) is as shown in the description), wherein in the formula (I), R1 is the residue of diisocyanate with -NCO removed or the residue of polyisocyanate with -NCO removed, R2 is the residue of single-end hydroxyl polyethylene oxide with terminal hydroxyl removed, R3 is the residue of amino acid with -NH2 removed, and the amino acid comprises at least one chain segmentcontaining -COOH and at least one chain segment containing -NH2; and in the formula (I), 0＜m≤9，0＜n≤9. The polyesterhyperdispersant provided by the invention is introduced in a salification process in preparation of the isocyanate, so that the agglomeration phenomenon can be avoided, the flowability of a diamine hydrochloride solution is improved, and the production efficiency is improved.