An antenna with an improved holed system ground plane comprises a substrate, a radiation conductor member, a grounding member and a system ground plane. The radiation conductor member is arranged on the surface of the substrate. The grounding member is arranged on one edge of the substrate. The radiation conductor member is connected with the grounding member. The system ground plane is connected with one side of the grounding member. The system ground plane has at least one arbitrary-shaped hole. A radiation-enhancing filler is disposed in the arbitrary-shaped hole. The present invention solves the conventional problems that the system ground plane is drilled or cut to accommodate components and IC chips, keep away from wiring routes and avoid protrusions on the appearance, via disposing radiation-enhancing fillers in the arbitrary-shaped holes. Thereby is kept integrality of the system ground plane and promoted omnidirectionality of signal transmission.