A matrix alkyd resin was synthesized using oleic acid, pentaerythritol, phthalic anhydride, and benzoic acid as raw materials and propylene glycol methyl ether acetate (PMA) as a solvent; benzoyl peroxide ana tert-butyl peroxybenzoate double initiators were used to initiate the copolymerization of olefin monomers in steps to prepared. A styrene-acrylic resin was modified and a water-based alkyd resin was prepared. The effects of different oil degrees on the structure and properties of water-based alkyd resins were studied. The structure, stability and emulsion properties of the resin were characterized by Fourier transform infrared spectroscopy (FTIR), thermal weight loss (TGA), and laser particle size scattering (DLS). The film properties of the resin were measured, including water resistance, surface drying time, hardness, salt spray resistance, and electrochemical properties. The results show that when the molar ratio of oleic acid: pentaerythritol: terephthalic anhydride: benzoic acid is 1: 1: 1: 0.3 mol and the oil degree is 47%, the particle size of the polymer emulsion is 74.4 nm, and the PDI is 0.262. The water absorption of the film is 14.5%, the contact angle is 70.87 ?, and has good water resistance. The surface drying time of the modified alkyd resin is shortened to 0.5 h. The dry time of the modified alkyd resin is shortened to 24 h, and the hardness reaches HB.