In this paper, the effect of calcium (Ca) additions on microstructure, texture and mechanical properties of Mg-4Zn alloy has been investigated. The as-cast alloys consisted of α-Mg dendrites and MgZn phase, and Ca addition also caused the formation of ternary Ca2Mg6Zn3phase. Results showed that Ca elements significantly refined the grain size of extruded sheet and weakened the strong basal textures. Along the transverse direction (TD) of sheet, Mg-4Zn-0.3Ca alloy exhibited an ultimate tensile strength (UTS) of 260 MPa, tensile yield strength (TYS) of 163 MPa. Moreover, the elongation to failure of Ca containing alloy increased up to 24% compared to that of 19% for Mg-4Zn alloy. The recrystallization mechanism and texture evolution of the alloy have been analyzed. What"s more, the strengthening and toughening mechanism, includes the anisotropy of mechanical characteristics, both have been studied.