The invention belongs to the field of chemical engineering technology, in particular to an ultraviolet-curing water polyurethane coating and the preparation method thereof. The preparation method comprises the following steps: introducing polythiol and alkene respectively serving as end groups into a polyurethane pre-polymer terminated by polyester polyol or isocyanate by chemical bonding; preparing the water polyurethane dispersion coating containing polythiol and polyalkene by the self-emulsification method; and preparing the ultraviolet-curing water polyurethane coating with a solid content of 15 to 55% on the basis of the two polyurethane water dispersion coatings. The coating of the invention has the advantages of excellent storage stability at room temperature, high ultraviolet curing speed, uniform curing degree, high conversion rate of functional group (almost up to 100%), and no oxygen block effect, and can be used in the fields of environmental protection, building, household appliances, automobiles, optical disks, optical fibers, etc. The inventive method has the advantages of simple and environment-friendly process, high coating quality, high input-output ratio, low cost and wide application prospect.