The invention discloses a phosphorus-containing indoor-temperature high-plastic-deformation magnesium alloy which comprises the chemical components in percent by mass: 5.5-8.5 percent of Al, 0.4-1.5 percent of Zn, 0.1-1.0 percent of Mn, 0.05-1.0 percent of P and the balance of Mg and impurities. According to the phosphorus-containing indoor-temperature high-plastic-deformation magnesium alloy, a nonmetal element P is mainly added in an existing magnesium alloy smelting process, a stable and fine grain structure is obtained through the action of the nonmetal element P, the room-temperature plasticity of a magnesium alloy is improved, and the room-temperature processing and using requirements of a finished product or a semi-finished product are met.