Abstract: Acquiring the direction information from the laser threat is one of the most crucial techniques of laser warning. This paper focused on a novel method which based on cylindrical lens and measuring laser incident direction with non-imaging mode to acquire the direction information. The laser warning system was composed of two perpendicular linear array devices, each of which included a cylindrical lens group and a linear IRFPA. The laser incident direction was defined by azimuth and pitch angle which could be calculated by the offset of line spot in the IRFPA. The principle of this method, the structure of laser system, the error analysis were mainly discussed in this paper. And a simulation was made in the end. The simulation result shows that this new kind of laser warning system can achieve pitch angle of 16 is valuable for applying laser warning system on motor vehicles, planes and satellites.