Abstract: Path planning using TF/TA² (terrain following, terrain avoidance, threat avoidance) technology is the key problem for the research in penetrating aircraft to fly at low altitudes. The terrain information is stored in a real digital map. To make sure the designed path applicable for the aircraft, preliminary treatment for the digital map was researched. A virtual terrain surface was constructed by combining the information of terrain, threat and aircraft performance. The treatment included compressing the original data file, transforming threat information to terrain height information, interpolating data at the point where the original terrain information could not be got, and smoothing the terrain surface. By devising a cost function considering the requirements of TF/TA², translating its form to the A^* algorithm, and using some optimization methods, three-dimensional path generation for the vehicles using TF/TA² could be realized. The simulation results demonstrate the validity of the algorithm.