Sizing agent as well as preparation method and application thereof

The invention discloses a sizing agent and a preparation method and application thereof, and belongs to the technical field of fiber composite material preparation. The sizing agent comprises the following main components: bisphenol A epoxy resin, vinyl modified bisphenol A epoxy resin and polyurethane modified epoxy resin, wherein the mass ratio of the bisphenol A epoxy resin to the vinyl modified bisphenol A epoxy resin to the polyurethane modified epoxy resin is 100: (25-100): (50-100); the bisphenol A epoxy resin, the vinyl modified bisphenol A epoxy resin and the polyurethane modified epoxy resin are synergistically matched to form the final sizing agent emulsion, so that the carbon fiber has relatively low hairiness amount. Meanwhile, the sizing agent can be simultaneously applicable to preparation of composite materials with epoxy resin and vinyl ester resin matrixes as matrixes, so that the composite materials with the epoxy resin and the vinyl ester resin matrixes as the matrixes can have better inte