microstructure and properties of high Zn Mg alloy was investigated. The kindling point of Mg alloy with Zn 20%~25% and Al 5%~10% is more than 740 ℃ and density of the Mg alloy is approximately 2.2g/cm 3. Conventional casting technology could be adopted to produce the Mg alloy casting with tensile strength 145~164 MPa.