Magnesium (Mg) alloys have various applications in the electronics, automobile, and aerospace industries due to their special material properties. It is generally believed that Magnesium-Calcium (Mg-Ca) alloys can be used for biodegradable implants. Mg-Ca alloys can be safely absorbed in the human body and they offer superior mechanical properties when compared to the current degradable polymers used for temporary implants. However, very few studies have been done on the mechanical properties and microstructures of Mg-Ca alloy. In this study, the Mg-Ca0.8 mechanical properties were obtained using the quasi-static and split-Hopkinson pressure bar (SHPB) materials tests. The experimental elastic modulus for Mg-Ca0.8 was 44.9 GPa. Some trends in the stress-strain curves were an increasing ultimate strength and yield strength with increasing strain rate from medium to high levels. The average grain size of undeformed Mg-Ca0.8 was 500 microns. The microstructure of Mg-Ca0.8 alloy had branch-like grain boundaries similar to the microstructure observed in magnesium alloy Mg3Al1Zn.