With the increasing number of unmanned aerial vehicles (UAVs), the increasing pressure of air traffic management and airspace security, it is a challenge to achieve effective UAV target detection. Computer vision and radar signal detection are two commonly used technologies in this field. Computer vision is limited by meteorological conditions and the radar signal is affected by ground clutter at low altitudes. In response to these problems, this paper describes the information fusion method from two different levels of data-level fusion and decision-level fusion. In this method, Computer vision and radar signals complement each other to improve the detection accuracy. For each level, the method of information fusion is introduced in detail. Besides, the effectiveness of the method is proved by comprehensive experiment. The results show that the accuracy of the fusion method is improved, with a maximum of 9.0%.