A magnesium alloy shown includes magnesium as a principal ingredient, and 0.5 to 8.0 percent ytterbium; 0.1 to 2.0 percent calcium; and 0.2 to 6.0 percent zinc, percentages calculated by weight. The magnesium alloy may be employed as an implant. Examples of implants include a plate, specifically a bone plate, a screw, a nail, a bone nail, a stent, a rod. Implants made of the specified alloy are suitable for implantation in animal or human body.