Path planning methods for air penetration are mainly based on electromagnetic interference to reduce the radar detection area, such as A* algorithm for route planning. These methods are suitable for occasions with a few detection overlapping areas of radar network, but they are not accurate for the description of radar network’s capability and unable to indicate the threat state along the penetration route. To address this issue, this paper analyzes the basic principles for warning radar network, casts the air penetration process as a Markov decision process(MDP), and proposes one planning algorithm based on the heuristic search. Simulation result shows that this method can not only improve the penetrating probability of air aircrafts, but also provide threat state for pilots along the penetration route.