The invention relates to the technical field of metal material magnesium alloy preparation, and particularly provides a preparation method of a biomedical magnesium alloy wire. The preparation methodof the biomedical magnesium alloy wire comprises the steps that a magnesium-zinc-neodymium alloy is subjected to the processes of smelting, casting, rolling and the like to prepare a plate, the plateis subjected to a special mechanical stirring process to prepare a machining area having the same thickness with the plate, the machining area is subjected to machining treatment and then taken as a final product of the wire or subjected to multiple passes of drawing, and the wire with the needed diameter is finally formed. According to the preparation method of the biomedical magnesium alloy wire, the rolling and the mechanical stirring processes are introduced, therefore, the forming property of the wire is improved, alloy grains are significantly refined, the size of a second phase is significantly decreased, most of the second phase are solid soluble in a matrix, the strength, especially the elongation, of the obtained wire is significantly improved, the good corrosion resistance is achieved, and the property requirements of the medical magnesium alloy wire are met.