The invention provides a water-emulsifiable nitrolacquer and a preparation method thereof. The water emulsion nitrolacquer comprises the following components in percentage by weight: 70%-90% of water-base nitro resin, 0.2%-0.5% of defoaming agent, 0.1%-0.5% of preservative, 2.5%-1% of substrate wetting agent, 3%-5% of sanding wax, 0.2%-0.6% of thickening agent, 1%-2% of antifreeze, 0%-0.2% of pH adjusting agent, 1%-3.5% of film forming auxiliary agent and 4%-20% of water. The water emulsion nitrolacquer has the advantages of good penetration property, quick drying, good sanding property, no adhesion to sand paper, little odor and no toxicity, and can be used as American water-base full-open spray after being produced. The product conforms to national standards and law regulations when exported to American and European Union, and has little odor; and the nitrolacquer film has the advantages of good sanding and adhesion property, quick drying and the like, thereby being suitable for flowline production.