The invention provides water-based paint and a preparation method thereof. The preparation method comprises the steps that (1) ball-milling is carried out on copper powder, nickel powder, zinc oxide,talcum powder and calcium carbonate to obtain a ball-milling substance, then solvent thermal reaction is carried out on the ball-milling substance, silica gel, castor oil fatty acid and ethyl alcohol,and lastly, drying is carried out to prepare a component A; (2) sodium silicate, styrene-acrylic emulsion, a sodium hexametaphosphate aqueous solution and ammonium hydroxide are mixed to prepare a component B; (3) the component A and the component B are blended to prepare the water-based paint. The water-based paint has excellent dispersity and lustrousness, and the preparation method has the advantages that the process is simple, and the raw materials are easy to obtain.