The invention discloses a betaine type zwitterionic polymer antifogging coating and a preparation method thereof. The coating is prepared from components as follows: 77%-100% of a random copolymer p (BMAm-co-FMAn-co-AMAr) and 0-23% of polyethylene glycol dimethacrylate; the coating is prepared from a betaine type zwitterionic polymer with a crosslinking point and polyethylene glycol dimethacrylate as a cross-linking agent through ultraviolet curing and film-forming, and is a random copolymer formed by betaine type acrylate monomers, fluorinated acrylate and allyl methacrylate through free radical polymerization. Hydrophilic betaine type zwitterionic components are subjected to hydration with water to realize the antifogging effect; with introduction of an appropriate quantity of hydrophobic components, water vapor can be effectively isolated, and interaction of a hydrophobic part and water is not influenced; the crosslinking point is provided by allyl methacrylate, so that stability of the coating is improved; the coating has good transparency and antifogging performance, and light transmittance of the coating in a visible light wavelength range reaches 80% or higher.