In　this　paper,　the　theory　of　Quasi-steady　is　applied　to　the　calculations　of　turbochargers　matching　to　the　diesel　engines　and　performance　prediction.　The　engine　performance　prediction　programs　written　in　language　C　have　been　used　for　calculations　of　various　turbocharged　diesel　engines.　It　has　been　confirmed　by　the　comparisons　with　experimental　data　that　the　results　of　the　calculation　are　reasonable,　reliable　and　satisfied　for　the　engineering　applications.　©　1992　Science　Press.