Abstract: Based on the theory of homing point excursion link against anti-radiation missile(ARM),a method of decoying ARM by excursion link was proposed,and the mathematical model on calculating the ARM's resolution distance and guiding probability was established.The operational effectiveness assessment model of 3 unit excursion link was presented,then the influence of radiant points' working time,distance,ARM's resolution angle and velocity on decoy effect was analyzed and the relation curves were given.The results show this method is effective.Compared with the additive radiant points working together,the excursion link decoy doesn't require the equal amplitude signals in seeker input and the accordant power and phase for radiant points,so the project is easier to be carried out,and every radiant point doesn't influence each other,it is also facile to control them.