An antenna structure for mobile phone comprises a PCB (printed circuit board), an antenna portion and a second grounding portion position connected to the PCB. A face of the PCB is smeared with a stratum metal material and functioning as a first grounding portion. The antenna portion further has an antenna, a feeding point and a grounding point connected with the antenna. The second grounding portion connected to the PCB on another side of the PCB opposite to the antenna portion. Because the area of the grounding portion is increased, the electric field could be equality distributed within the whole grounding portion.