The invention discloses an anion composite powder suitable for building materials. The anion composite powder is prepared from, by mass, 30-80 parts of schorl powder, 1-30 parts of Qicai powder, 1-8 parts of sodium hexametaphosphate, 1-5 parts of zinc oxide, 0-30 parts of rare earth, 1-30 parts of ferroferric oxide powder, 1-8 parts of water-borne acrylic acid and 1-8 parts of monazite powder. According to the anion composite powder in the technical scheme, a preparing technology is simple, and the price of the raw materials is low; an anion plate has perdurability, efficiency and the environment-friendly performance, the prepared anion plate can efficiently and stably release anions with the density of 2,200-4,000 per s.cm<2>, air can be purified, indoor peculiar smells and harmful gas can be removed, and the anion composite powder is an environment-friendly anion additive.