The invention discloses water-based polyurethane composite adhesive for tanning and a preparation method and application of the composite adhesive, belongs to the technical field of water-based polyurethane composite adhesive preparation methods, and in particular relates to a method for preparing composite adhesive in the fields of artificial leather and synthetic leather. The method for preparing the water-based polyurethane composite adhesive for tanning is characterized by comprising the following steps of: reacting polyol polymer and isocyanate, adding chain extender, hydrophilic chain extender, cross linker, catalyst and solvent, reacting, cooling and emulsifying, to obtain emulsion; and mixing the emulsion, curing agent, wetting agent, tackifier, adsorbent and thickening agent uniformly, and thus obtaining the hot-melt adhesive for artificial leather adhesive layers. The water-based polyurethane composite adhesive for tanning is used for compounding polyvinyl chloride (PVC) / cloth for artificial leather of luggage and clothes. The prepared water-based polyurethane composite adhesive for tanning has high adhesive fastness and good water and solvent resistance, and can be applied to processes of knife coating, roll coating and the like of binding materials of middle layers of artificial leather and synthetic leather in the fields of textiles, leather processing and the like.