The invention provides a nanometer itraconazole external preparation and a preparation method and a use thereof, and the nanometer itraconazole external preparation comprises components of nanometer itraconazole and a matrix, wherein the matrix is selected from the multiple components of octodecyl alcohol, cetyl alcohol, stearic acid, isostearic acid, glyceryl monostearate, white vaseline, sodium lauryl sulfate, glycerin, liquid paraffin, solid paraffin, tween-80, tween-60, span-60, span-80, polyethylene glycol 4000, polyethylene glycol 400, polyethylene glycol 200, carbomer, propylene glycol, ethanol, benzyl alcohol, triethanolamine, carboxylation methyl cellulose, EDTA (ethylenediamine tetraacetic acid) or methyl hydroxybenzoate, and the content of the nanometer itraconazole is 0.1% by weight-10% by weight. By adopting the nanometer itraconazole external preparation, the shortcomings that the itraconazole is difficult to absorb in the external preparation, the skin penetration is not high and the percutaneous absorption rate of the itraconazole is not high are solved, the hepatotoxicity of the itraconazole during metabolism process of a human body is avoided, the bioavailability is improved, and a new administration way is provided for a patient.