The invention discloses an environment-friendly high-strength stone-plastic board. The environment-friendly high-strength stone-plastic board comprises the following raw materials in parts by weight: 10-16 parts of marble powder, 8-12 parts of fly ash, 10-14 parts of volcanic ash, 6-10 parts of talcum powder, 17-27 parts of polyethylene, 8-10 parts of chlorinated polyethylene, 4-6 parts of nano-sized titanium dioxide, 2-4 parts of nano-sized zinc oxide, 2-5 parts of a lubricant, 2-3 parts of a plasticizer, 1-3 parts of a stabilizer, 2-4 parts of an antistatic agent and 3-5 parts of a silane coupling agent. The environment-friendly high-strength stone-plastic board combines the advantages of stone and plastic, not only has the appearance like natural stone, but also is relatively light in weight, relatively high in strength, anti-static, non-friable and relatively environment-friendly; meanwhile, according to a preparation method of a sealing material provided by the invention, raw material components are safe, reliable, harmless to the environment and easy to obtain, the cost is relatively low, the process is succinct, the operation is easy and the industrial production is easily implemented, so that the preparation method has a relatively high practical value and a good application prospect.