The invention discloses a preparation method of waterborne alkyd enamel. The preparation method comprises the following components in percentage by mass: 45%-55% of waterborne alkyd resin, 10%-15% of rutile type titanium dioxide, 0.3%-1% of carbon black, 10%-15% of precipitated barium sulphate, 0.2%-0.5% of a waterborne dispersing agent, 0.1%-0.2% of a waterborne antifoaming agent, 0.1%-0.2% of a waterborne foam inhibitor, 1%-2% of hydrated magnesium silicate, 0.8%-1.2% of waterborne drier, 0.2%-0.4% of a waterborne anti-skinning agent, 0.5%-1% of a water-based thickener, 2%-4% of a neutralizer, 2%-4% of a hydrotropy agent, 2%-4% of a coalescing agent, 0.1%-0.2% of a waterborne flatting agent and 8%-9.6% of deionized water. The method comprises the following technological steps: stirring the waterborne alkyd resin evenly, and testing and adjusting the pH value; diluting the foam inhibitor with the deionized water, then adding to a production cylinder, stirring, and adding the rutile type titanium dioxide and the like, dispersing and then grinding; adding a compound drier and the like, and stirring; adjusting the viscosity with the deionized water; and adjusting the pH value of the product with the neutralizer. The waterborne alkyd enamel has the advantages of being high in drying rate, high in glossiness, excellent in weather fastness, excellent in salt water resistance, and free of a blistering or rusting phenomenon after being soaked in a 3% sodium chloride solution for 480 hours.