The invention discloses an improved environmental protection building board, which comprises the following raw materials in parts by weight: 25-35 parts of cement, 4-5 parts of slag, 2-3 parts of fly ash, 1-2 parts of ordinary sand, 1-2 parts of rock removal, 1-2 parts of magnesium borate, 2-4 parts of paraffin, 3-5 parts of sulfomethyl phenolic resin, 2-3 parts of AR glass fiber, 2-3 parts of carboxymethyl cellulose, water reducing 0.6-1.2 parts of agent, 0.4-0.6 parts of foaming agent, 0.4-0.6 parts of foam regulator, 0.1-0.2 parts of catalyst, 0.3-0.6 parts of crosslinking agent, 0.1-0.2 parts of foam stabilizer, 20-20 parts of glyoxal 24 parts, hydrogen peroxide 12‑18 parts, water 210‑240 parts. The board prepared by the invention has excellent performances of light weight, heat preservation, fire prevention, high strength and environmental protection, and its performance index is far higher than the requirements of national and industry standards.