By analyzing the typical operational processes of ship-borne anti-missile system in intercepting anti-ship missile and the damaging mechanism of the warhead of the ship-to-air missile,a quantitative analysis is made to the motion characteristics of the warhead preposed fragments,and the surface density model of the fragment is established. Pk/h function is used as the damage describing criterion to establish the damage probability model of the ship-to-air missile for one interception of anti-ship missile;and Markov chain is used for establishing the damage probability model of multiple interceptions.The feasibility and reliability of the model have been verified by the simulation analysis.Some suggestions are given for optimizing the intercepting strategy,which can provide a reference for the commanders to make operational plans.