本发明提供一种基于成盐光气化法制备低氯代杂质含量异氰酸酯的方法。该方法成盐反应获得的盐颗粒粒径分布在平均粒径±30％范围内的比例占总粒径分布的70％以上，无搅拌的平均停留时间小于60min。相对于传统的方法，该方法获得的产品具有更低的氯代杂质含量。

The invention provides a method for preparing isocyanate with low chlorinated impurity content based on a salifying phosgenation process. According to the method, the proportion of salt particles obtained by a salifying reaction and having particle sizes 30% bigger or smaller than an average particle size accounts for 70% or more of the total salt particles, and mean retention time without stirring is less than 60 minutes. Compared with a traditional method, a product obtained by the method has lower chlorinated impurity content.