Modified polyurethane

The invention relates to a modified polyurethane which is composed of a bridging agent, diisocyanate, a catalyst 1, dibasic alcohol and a solvent. The diisocyanate is dropwisely added into a mixture composed of the bridging agent catalyst 1, dibasic alcohol and solvent, and the mixture is stirred to react under certain conditions to obtain the modified polyurethane. The bridging agent is composed of a coupling agent, deionized water, a catalyst 2 and ethanol; the organo-functional group modified organic silicon, organic zirconium, organic titanium and other chain segments are introduced by the coupling agent, thereby correspondingly increasing the compatibility with nano silicon dioxide, nano indium tin oxide, nano titanium dioxide or any other nano powder; and therefore, the modified polyurethane can improve the dispersivity and storage stability of the nano powders in the paint, and overcomes the defects of poor dispersivity, high soft aggregation tendency and the like in the existing nano powders which are