A guard ring applied to an ion implantation equipment is disposed between a bushing and an ion beam source housing of the ion implantation equipment. The guard ring is made of high-density ceramic material. The guard ring can prevent arcing generated by the high voltage used for ion implantation from causing unpredicted damage to the bushing, thereby effectively protecting the ion implantation equipment, increasing the lifetime of use of the ion implantation equipment, and lengthening the maintenance cycle.