The complexity of modern weapon systems using the IT(intelligence technology) demands that rapid and effective transition from force requirements to deployment and fielding. Thus this paper deals with the DT&E(developmental test & evaluation), OT&E(operational test & evaluation) and SBT(simulation based test) procedure using the case study in the test & evaluation of weapon systems. This study is aimed to produce the effective test & evaluation method of weapon systems in the change of acquisition environment.