A　novel　abstract　model　for　the　design　of　trusted　computing　platform　system　was　proposed.　By　using　the　basic　idea　of　non-interference　theory　as　reference　and　introduces　the　reasoning　method　of　process　algebra,　thus　abstracting　the　system　as　processes,　actions,　states　and　outputs,　and　giving　the　formal　definition　of　the　trusted　of　process　running.　Process　isolation　trusted　theorem　was　verified　formally.　Furthermore,　by　associating　process　with　system　state,　the　definition　and　the　theorem　of　system　running　trusted　was　proposed.　The　model　was　established　by　logic　reasoning　and　independent　of　special　security　mechanism　and　enforcement.　The　trust　of　the　running　system　can　be　realized　by　any　method　which　satisfies　the　conditions　of　the　model.