The invention discloses a cationic self-matting resin, and a preparation method and application thereof. The cationic self-matting resin comprises isocyanate, a diamine cationic hydrophilic chain extender, macropolyol, monohydric alcohol and/or dihydric alcohol with the main chain and/or the side chain containing a polyoxyethylene chain, a small molecular diamine chain extender, a catalyst, a solvent and a neutralizing agent. The preparation method has the advantages of simple process, convenience in operation, safety and non-toxicity, and the obtained cationic self-matting resin has the advantages of small particle size fluctuation, good emulsion stability and resistance, good adhesion to anionic leather, glass and other substrates, and bringing of soft and smooth hand feeling and naturalrich appearance for leather, and can be widely applied to the fields of leather finishing, wood plastics, paper printing, printing and dying inks, printing coatings, packaging coatings and matt nailpolish.