The invention discloses a water-based adhesive, and a preparation method and application thereof. The water-based adhesive is composed of a water-based polyurethane emulsion, a water-based acrylic emulsion, a vinyl acetate-ethylene copolymer emulsion, a butadiene-styrene latex, a water-based terpene resin emulsion, redispersible latex powder, starch, methanol, a mildewproof bactericide and water. The preparation method comprises the following steps: 1) heating the mixture of starch and water to gelatinize, thereby obtaining a starch emulsion; 2) adding a water-based polyurethane solution and methanol A into the charging basket to obtain a mixed solution; 3) adding the starch emulsion into the mixed solution to obtain a semifinished solution; and 4) sequentially adding the other components into the semifinished solution in the step 3) to obtain the water-based adhesive. The water-based adhesive is used for bonding soft PVC (polyvinyl chloride) foamed materials. The adhesive has the advantages of high bonding strength, high drying rate, environment friendliness and no toxicity, and is especially suitable for bonding soft PVC foamed materials.