In this paper, effects of strontium on Mg alloys and preparation technology of Mg-Sr and Mg-Sr-Al master alloys were summarized respectively. Prospects and applications of Sr-Mg master alloys were analyzed too. The results showed that thermodynamics calculation of reaction between SrO and Mg(l) showed that molten Mg can reduce SrO, in which excess of molten. The microstructure of hypoeutectic Mg-Sr binary alloys is composed of primary Mg matrix, and laminary eutectic phase(Mg-Mg17Sr2),but the microstructure of Mg-Sr-Al alloy consists of plate-like primary Al4Sr, laminary eutectic phase (Mg-Mg17Sr2 or Mg-Mg17Al12 or Mg-Mg17Sr2-Mg17Al12) embedded in primary dendrites of magnesium matrix. Additive strontium in Mg alloys can refine it grains, reduce degree of porosity, improve mechanical and thermal properties, therefore, Mg-Sr master alloys can be served widely as an additive for modification or as a constituent of Mg alloys, Al alloys, Zn alloys, etc.