The present invention relates to a modified polyisocyanate and use thereof, in particular as a crosslinking component of water-soluble or water-dispersible coatings. The modified polyisocyanate is obtained by a reaction of a system comprising the following components: at least an aminosulfonic acid; at least a polyisocyanate; at least a tertiary amine; and optionally a polyether alcohol containing an ethylene oxide group. The modified polyisocyanate comprises at least an iminooxadiazinedione structure and at least an isocyanurate structure, the weight ratio of the iminooxadiazinedione structure to the isocyanurate structure being 1:300 to 1:5. The amount of sulfonate group of the modified polyisocyanate is 0.75% by weight to 1.1% by weight, based on the amount of the modified polyisocyanate as 100% by weight. The viscosity thereof is 500 mPa·s to 10000 mPa·s, as determined according to DIN EN ISO 3219:1994-10 at a temperature of 23° C. and a shear rate of 10 s−1. The coating comprising the modified polyisocyanate of the present invention can be manually stirred well, and the resulting coating layer has high gloss and good transparency.