Abstract: In this paper, a novel omni-directional high-gain collinear printed structure is presented, by designing an array of 4 antenna elements at 2.4GHz. Prototype of the proposed antenna have been constructed and tested. The experimental results show that the antenna has good omni-directional radiations and high gain, and the conundrums such as complicacy of design and difficulty in realization are solved, which indicate the validity of this method. The proposed antenna with relatively low profile is suitable for the WLAN communication.