The Mg-3Zn-1Y-0.6Zr-0.5Ca bio-magnesium alloy was prepared by conventional casting method. The effect of the microstructures and mechanical properties of alloys extruded at different extrusion speeds (10, 30, 60 and 90 mm / min) was investigated. Results show that the size of dynamic recrystallization grains increases and the area of non-dynamic recrystallization decreases with increasing the extrusion speeds. Extrusion speeds affect the morphology and distribution of the precipitation, which affects the occurrence of dynamic recrystallization in turn. Texture decreases with increasing the extrusion speed. As the extrusion speed increases, the ductility of the alloy increases but the tensile strength decreases. The alloys exhibits excellent comprehensive performance, whose tensile strength and elongation are 270Mpa and 19.6% when the extrusion speed is 60mm/min.