This study proposes an additive manufacturing method for high-strength Mg-RE alloys, which optimizes the strengthening effect of long-period stacking ordered (LPSO) structures through severe plastic deformation induced by friction rolling additive manufacturing (FRAM). Using multi-wire winding as the feed material, Mg-9Gd-4Y-1Zn-0.4Zr samples were successfully fabricated. The results show that the deposited structure is dense, with no observable cracks, pores, or other defects. Although some wires are not directly stirred by the tool head, they undergo extrusion under thermal influence. Grains subjected to direct stirring and rolling are significantly refined, with a notably enhanced recrystallization degree. Severe plastic deformation induced by FRAM leads to the refinement and dispersion of LPSO phases, which further inhibit the growth of recrystallized grains, resulting in an average grain size of only 1.8 μm. Consequently, the joint achieves an ultimate tensile strength of 375   MPa.