The invention relates to a quick-drying hydroxyacrylic resin aqueous dispersion with long working life and a preparation method thereof. Metal ions are chelated in the aqueous dispersion and are used as a catalyst, and in an aqueous phase system, a catalyst component is wrapped by a hydrophobic core layer of the dispersion, but is not contacted with an isocyanate component, so that the activation period is not shortened; in the later stage of construction, moisture is basically evaporated completely, a hydrophobic part inside the dispersion is contacted and fused with the isocyanate component, and the metal catalyst starts to catalyze a reaction of the hydroxyl group and the isocyanate to promote curing of a coating film, so that the aqueous dispersion has the characteristics of long working life and quick drying. When the aqueous dispersion is applied to a waterborne double-component polyurethane coating, the coating film has excellent gloss and fullness, high hardness, good flexibility, excellent water resistance and solvent resistance; the aqueous dispersion can be widely applied to coating of wood furniture and large transporting tools, industrial coating and automobile repairing.