1HA/Mg-3Zn-0.2Ca composites (wt%) were fabricated by melt high shearing technology followed by hot extrusion. Effects of heat treatment on microstructures, mechanical properties and corrosion resistance were investigated. The results indicate that after solid solution treatment (T4 treatment), the amount of secondary phases in 1HA/Mg-3Zn-0.2Ca composite decreases, grain size becomes larger, yield strength decreases, while the elongation and the corrosion resistance increases. However, the corrosion resistance shows a decreasing trend as the solid solution treatment time exceeds 3 h, which is attributed to overlarge grain size. After solid solution and aging treatment, the yield strength increases while the corrosion resistance does not change obviously. Hence, the corrosion resistance and elongation of the as-extruded 1HA/Mg-3Zn-0.2Ca composite can be improved by proper solid solution and aging heat treatment.