The invention discloses water-based environment-friendly radiator paint and a preparing method thereof. The water-based environment-friendly radiator paint comprises, by weight, 20 parts to 25 parts of water-based self-crosslinking acrylate emulsion, 10 parts to 15 parts of polyurethane emulsion, 6 parts to 8 parts of passivation liquid, 5 parts to 7 parts of acrylic-silicone emulsion, 4 parts to 6 parts of chitosan, 5 parts to 7 parts of adhesion pigment, 0.6 part to 0.8 part of defoaming agents, 0.03 part to 0.05 part of flatting agents, 12 parts to 15 parts of plant water-based color paste, 0.4 part to 0.6 part of cellulose acetate, 0.5 g/L to 0.7 g/L of penetrating agents JFC, 0.2 part to 0.5 part of pentachlorodiphenyl and 100 parts of deionized water. By means of the water-based environment-friendly radiator paint and the preparing method, the water paint spraying film forming speed is increased, and a passive film is good in corrosion resistance, low in porosity, rich in plant ingredient, nontoxic, environmentally friendly and low in smell, and has the certain antibacterial effect and the certain fireproof performance; the surface adhesive force of the radiator paint is improved, the luster is bright, the crack resistance is improved, the workpiece bonding performance of the environment-friendly radiator paint can be improved, the effect that repeated adhesion of the surface of the radiator paint can be avoided after the radiator paint is dried is achieved, and the excellent water resistance is achieved.