With the continuous development of air defense system in information battlefield,the path obtained by constant-weight cost function has great deficiency in aircraft survivability.Thus we improved the traditional constant-weight cost function with variable weight theory.In simulation,the results of path planning based on the constant weight and variable weight cost function were analyzed with Differential Evolution Algorithm (DEA).The result proves the feasibility of the path planning method based on variable weight theory,and shows that it can greatly improve the aircraft battlefield survivability.