In this study, various amount of Mn elements (x=0.4, 0.8, 1.2, 1.6, 2.0, wt. %) was added to Mg-10Gd-6Y-1.6Zn alloys. We investigated the effect of Mn elements and extrusion ratio on the microstructures and mechanical properties of the alloys. The results show that in the hot extrusion Mg-10Gd-6Y-1.6Zn-xMn alloys, the metastable 18R structure turned into a stable 14H structure of the long period stacking ordered (LPSO) structures. Large extrusion ratio can significantly improve mechanical properties of the alloys at room temperature. When 0.8 wt.% Mn element was added to the alloy, its tensile strength of no-aged status is 386 MPa, and its elongation is about 10%.