The Mg-10Gd-3Y-1Sn alloys were prepared by centrifugal casting and hot rolling, and their microstructure and mechanical properties were investigated by X-ray diffraction, optical microscope, scanning electron microscope, and tensile tests. Results show that the centrifugal-cast Mg-10Gd-3Y-1Sn alloy consists of α-Mg, Mg₂₄(Gd,Y)₅, Mg₂(Sn,Y)₃Gd₂, and Mg₃(Gd,Y) phases. With increasing the centrifugal radius and rotation speed, the tensile strength of alloys is increased gradually due to the decreased grain size of alloys. The ultimate tensile strength of as-rolled alloys after centrifugal casting with the rotation speed of 700 r/min is 304 and 296 MPa at room temperature and 300 °C, respectively. The improved tensile strength of Mg-10Gd-3Y-1Sn alloy at elevated temperatures mainly results from the Mg₂₄(Gd, Y)₅, Mg₂(Sn, Y)₃Gd₂, and Mg₃(Gd, Y) phases with excellent thermal stability.