The invention relates to the field of bathroom materials and in particular relates to an SAN/PMMA (Styrene-Acrylonitrile/Polymethyl Methacrylate) composite material for bathrooms and a preparation method thereof. The composite material is prepared from the following raw materials in parts by mass: 10 to 30 parts of a toughening agent, 30 to 55 parts of SAN, 15 to 40 parts of PMMA, 3 to 10 parts ofa styrene-acrylonitrile-maleic anhydride copolymer, 0.5 to 3 parts of a brightening agent, 0.5 to 3 parts of a light stabilizer, 0.5 to 3 parts of an anti-scratching agent and 0.5 to 2 parts of otherauxiliary agents, wherein the other auxiliary agents comprise at least one of a lubricant and an antioxidant. The SAN/PMMA composite material for the bathrooms, provided by the invention, can be usedfor manufacturing bathroom products and can meet special requirements on bathroom product materials, such as high luster, scratching resistance, weather resistance and acid and alkali corrosion resistance; the problems that existing ceramic bathroom products have relatively great weight, are inconvenient to transport, are easy to damage in a transportation process, have complicated processing procedures and relatively single color and the like can be improved; the SAN/PMMA composite material for the bathrooms has relatively good application market and prospect in the field of the bathrooms.