Mg-based alloy Mg80Zn16-xCa4Cux（x=2

4

6）with 2mm in diameter was prepared by means of copper mold casting based on the design of amorphous alloy composition forming rule.The microstructure

phase constituent and compressive behavior of the as-cast alloy were investigated by SEM（scanning electron microscope）

XRD（x-ray diffraction）and mechanical property testing device

and the fracture morphology of alloy was analyzed.The density of the alloy was obtained by using the Archimedes law and the specific strength was calculated.The Mg80Zn16-xCa4Cux alloy with x of 2

4

6 is 574.5

678.6

616.7 MPa in compressive strength

respectively

and 449.7

300.8

389.8 MPa in yield strength

respectively and 1.1%

4.6% and 4.0% in elongation

respectively

in which the Mg80Zn12Ca4Cu4 alloy has the highest both in strength and in plastic deformation in rare earth free Mg-based alloy reported up to now.