According to the route planning of air-to-ground attack of a fighter, this paper proposes a model of programming the air-to-ground airline based on PSO. Because the traditional arithmetic is low in constringency precision, based on the algorithm parameters and iterative expressions, the traditional algorithm is improved. Through constructing a variety of constrain conditions during attacking and fighting, such as antiaircraft fire, landform, technique and tactic performance of fighters etc., VC++.NET is used to conduct the algorithm simulation and the optimal airline is shown in MATLAB. The result suggests that the optimal route programmed by the modified PSO has a better performance of avoiding the threat, which satisfies the requirement of constrain technique and tactic performance and shorter voyage of fighters. And furthermore, the planning is better and higher in efficiency and precision.