Featured characteristic of inertial navigation system (INS) information, as short-term accuracy, ultra stability and self determination, cannot be disturbed by electromagnetic interference. In light of these traits, a novel information processing approach aided by INS position and velocity information for anti-jamming application was proposed,. Based on missile-to-target relative motion model，during the terminal guidance tracking phase of anti-ship missile (ASM), target position and velocity information could be obtained by extended Kalman filtering to suppress seeker random measurement errors. When the jamming was detected, one can combine target position forecast with INS navigation solution to accomplish the homing guidance of ASM, which could help achieve one's purpose of anti-jamming. Simulation was carried out in the presence of a maneuvering ship target, and it shows that this method is effective and feasible because of its preferable anti-jamming performance.