[en] The microstructures and tensile properties of extruded Mg-1Gd-0.5Zn-xCe sheets with various Ce contents (0, 0.3, 0.7 and 1.2 wt%) were investigated at room temperature. Ce addition refined the grain size and resulted in the formation of new Mg₁₂Ce phases. The volume fraction of Mg₁₂Ce phases increased with the increase of Ce additions, which impeded the growth of dynamic recrystallized grains during extrusion and consequently led to the texture weakening of Mg-1Gd-0.5Zn based sheets. Grain refinement and massive Mg₁₂Ce phases provided the highest strength in the Mg-1Gd-0.5Zn sheet with 1.2 wt% Ce addition. Moreover, due to more basal slip, pyramidal slip activity and uniform strain distribution, the ductility of extruded Mg-1Gd-0.5Zn sheet with 0.3 wt% Ce addition along the extrusion direction exhibited the maximum value of 33.6%, which was approximately 17.9% higher than that of the Mg-1Gd-0.5Zn sheet. However, with the further increase of Ce additions (0.7 and 1.2 wt%), the ductility of the sheets deteriorated gradually, which was associated with the increase of coarse Mg₁₂Ce particles.