The invention belongs to the technical field of acrylate polymer water emulsion, and discloses a UV (ultraviolet)-curable acrylate polymer water emulsion for coating a polypropylene film, and a preparation method and application thereof. The polymer water emulsion comprises the following components in parts by weight: 300 parts of water-based acrylic emulsion prepolymer, 1 to 5 parts of photoinitiator, 0.5 to 1 part of emulsifier, 0.5 to 1 part of flatting agent, 0.1 to 1 part of de-foaming agent, and 100 to 400 parts of water. The structure of the acrylate polymer water emulsion disclosed by the invention contains rich ester groups and alkyl groups, and can form acting force with the inorganic materials, such as glass, and organic interfaces, such as BOPP (biaxially-oriented polypropylene) plastic film; the polyether segment has high flowability and is soluble in water; the spreadability property of the emulsion on the BOPP film and the bonding property, the durability and the like of the emulsion on a cured film are improved; the UV-curable acrylate polymer water emulsion is favorable for the adhesive sealing and the fixing between the BOPP film and other plastics, glass, wood, metal, biological tissues and the like.