On the development trend of opening low altitude airspace in our country and the protection requirements for key areas, combined with the latest optoelectronic technology, a fast search method to detect low slow small target for low altitude airspace was presented, and a set of prototype system was developed. The system uses a linear CCD camera mounted on a high-precision one-dimensional turntable to collect 360-degree panoramic images of low altitude airspace. The image data is transmitted to the data processing workstation in real time through gigabit Ethernet slide ring. The data processing workstation detects small targets in the area above the skyline and figures out the orientation of target. Preliminary observation experiments of the prototype are conducted, the result shows that the system can detect low slow small target in broad low airspace in all directions. In the case of good atmospheric transparency, it can detect unmanned aerial vehicle (UAV) in size of 300 mm×300 mm×200 mm within 2300 m. The accuracy of the direction of measurement is 60 arcsecond. This research provides an effective mean to solve the problem of searching and finding low slow small targets.