In usual threat modelingthe information exchange among the threats is often ignored.To solve the problema target instruction probability model was established.On which basisa threat netting model based on detection probability was built up.Common path cost function was improved by using the threat netting model.The Differential Evolution Algorithm (DEA) was introducedand analysis was made to the effect of threat netting on threat intensity and threat cost of waypoint by using the method.Simulation was made to the effect of the threat netting model on path planningwhich shows the necessity and feasibility of threat netting model.