The invention discloses a Mg-Ca-Sr-Zn series magnesium alloy, a preparation method and application thereof. The magnesium alloy is composed of Mg, Ca, Sr and Zn; by weight percentage, in the magnesium alloy, the content of Ca is 0-5%, but not 0, and the content of Sr is 0-5%, but not 0, the content of Zn is 0-10%, but not 0, and the rest is Mg. The present invention regulates the mechanical properties and degradation speed of medical implants through the cooperation of composition design and preparation process, and obtains the best mechanical properties and corrosion resistance; it has better biocompatibility, mainly manifested in higher biocompatibility Cell survival rate, and the cell survival rate does not decrease significantly with the prolongation of culture time, has high ALP activity, good compatibility of red blood cells and hemoglobin; selects essential metal elements for human body, does not contain harmful or potentially harmful elements, of which The alloying element Sr in Mg-Ca-Sr-Zn series magnesium alloy can promote osteogenesis and inhibit bone resorption, so the local release of Sr along with the degradation of Mg‑Ca‑Sr‑Zn series magnesium alloy can promote tissue healing.