The invention discloses easily scattered precoated sand and a preparation method thereof. The easily scattered precoated sand is prepared from the following raw materials in parts by weight: 60-80 parts of zircon sand, 15-20 parts of river sand, 10-15 parts of montmorillonoid, 2-4 parts of thermoplastic phenolic resin, 0.5-1 part of anilino-methyl-triethoxysilane, 4-6 parts of triethyl citrate, 2-3 parts of polyvinyl formal, 10-15 parts of urotropine, 3-4 parts of urea, 1.5-2.5 parts of potassium dichromate, 4-6 parts of manganese ore slag, 2-3 parts of salicylic acid, 3-5 parts of butadiene-acrylonitrile rubber powder, 4-8 parts of ethylene bis-stearamide and 3-6 parts of composite powder. The precoated sand has excellent scattering property, the sand is easily cleaned after a casting is cooled and is subjected to sand shakeout, an inner cavity is smooth, the labor intensity of cleaning is obviously reduced, and the precoated sand has the characteristics of high strength, high liquidity, high air release amount, high heat resistance, high air permeability and the like. Moreover, the defects of sand adhesion, air holes, cracks and the like in the casting can be overcome, the surface quality of the casting is improved, and the precoated sand is suitable for production of nonferrous metal castings such as aluminum alloys and copper alloys.