The invention discloses a sand-fixing agent and its preparation method and application, belonging to the technical field of building materials, comprising A component and B component; wherein A component includes the following substances: styrene-acrylate polymer, polyvinyl alcohol- Epoxy resin, sodium alginate, zinc stearate; Component B includes the following materials: butyl stearate, 5-chloro-2-methyl-3(2H)isothiazolone, 2-methyl-3( 2H) Isothiazolone; and deionized water; and through stirring and mixing in an emulsification pot, heating, heat preservation, cooling, detection, and packaging to obtain a finished product. The sand-fixing agent of the present invention has excellent waterproof, mildew-proof, shock-resistant and curing effects, and has safe ingredients and is convenient to use, and can be applied to roof waterproofing, sand-fixing, dust-fixing, external wall sand-fixing, waterproof, wall moisture-proof, alkali resistance, Mildew proof, back water pressure waterproof, and underground engineering sealed and moisture-proof, so as to realize multiple purposes of sand-fixing agent, one thing with multiple purposes, convenient to use, and improve construction efficiency.