The invention belongs to the technical field of functional coatings, and in particular relates to a water-based fireproof and heat-insulating coating for wooden buildings and a preparation method thereof. The water-based fireproof and heat-insulating paint for wooden buildings mainly includes the following raw materials in parts by weight: 25-30 parts of silicon acrylic emulsion, 10-15 parts of ammonium polyphosphate, 6-8 parts of melamine, 3-6 parts of pentaerythritol, and rutile titanium dioxide 10-15 parts, 3-6 parts of hollow glass microspheres, 2-5 parts of sericite, 2.5-6 parts of hollow ceramic microspheres, 2-4 parts of nano far-infrared ceramic powder, 4-7 parts of diatomaceous earth, water-based enhancer 0.5-1 part of thickener, 0.2-0.4 part of water-based defoamer, 0.4-0.8 part of water-based wetting and dispersing agent, 0.1-0.3 part of water-based antifungal agent, 1-2 parts of film-forming aid, 20-30 parts of deionized water share. The method of the invention is simple, and the prepared coating is fireproof, heat-insulating, mildew-proof, high in adhesion, good in aging resistance, widely used and environmentally friendly, and can be used in wooden buildings for flame-retardant, reducing the temperature rise caused by strong sunlight radiation, and preventing indoor The heat is lost to the outside and other aspects have achieved beneficial effects, effectively protecting the building and saving energy.