This study is to predict the compressive strength for the concrete of ground granulated blast-furnace slag, and use Plowman`s, Gompertz`s model. The results are as follows; The prediction compressive strength were simiar using Rastrup``s equivalent age model. but The prediction compressive strength using Freiesleben ``s equivalent age model weren``t simiar in bfs replacement Ratio of 50%, because it is analyzed as the activation energy.