This paper on the Research of Naval Electronic Warfare System HILS(Hardware In the Loop System) describes the EW engagement HILS construction method for evaluation of the operational concept analysis on active RF Decoy in staying in the air and the deceit ability to anti-ship missile seeker. We obtain the EW M&S technology of EW engagement HILS and EW efficiency analysis from this project. This Naval Electronic Warfare System HILS technology will support Active Decoy Development Project and any other HILS of EW weapon in KOREA ARMY/NAVY/AIR FORCE.