In　conformance　testing,　it　is　crucial　to　have　short　and　efficient　test　sequences　for　faster　processing.　As　the　key　component　of　trusted　computing　platform,　the　conformance　testing　efficiently　for　trust　chain　is　very　necessary.　In　contrast　to　Unique　Input/Output(UIO)　sequence,　Backward　Unique　Input/Output(BUIO)　sequence　is　a　sequence　that　uniquely　distinguishes　a　state,　where　the　identified　state　is　the　end　state　in　the　sequence.　Therefore,　this　paper　focuses　on　the　algorithm　for　constructing　BUIO　sequences　of　trust　chain　specifications　FSM　model　based　on　successor　tree.　And　the　authors　analyze　the　test　sequence　generation　procedures　with　BUIO　sequences.　Empirical　evidence　indicates　that　the　proposed　method　yields　a　shorter　conformance　test　sequence　for　trust　chain　compared　with　UIO-based　method.　Copyright　©　2011　Binary　Information　Press.