This research paper on Tac-ELINT SW development method using M&S system describes the validation and verification methods of Tac-ELINT ground operating software development each stages, and the method of improving reusability of software using SBD(Simulation Based Design/Development) concept. In this project, We obtain the EW software SBD technologies and improved Tac-ELINT ground operating software through software crisis mitigation. This method and technology will expect to support a future EW system and any other various weapon software development.