The invention relates to a waterborne paint and a preparation method thereof. The waterborne paint is characterized by comprising the following raw materials by weight: 35-50 parts of organosilicon modified acrylic resin, 10-15 parts of methylated melamino-formaldehyde resin, 4-8 parts of methanol, 4-8 parts of dipropylene glycol butyl ether, 1-3 parts of filler and pigment, 0.1-1 part of a wetting agent, 0.1-1 part of an efficient defoamer, 0.1-1 part of a leveling agent, 0.1-0.5 part of a drier, 0.1-0.5 part of an antioxidant, and 40-60 parts of deionized water. The waterborne paint providedby the invention can achieve high hardness, good adhesion and wear resistance after spraying, also has excellent flexibility, water resistance and weather resistance, moisture and heat resistance andsalt spray resistance, also the preparation process is simple, and is suitable for large-scale production.