The　reliability　of　a　system　that　shares　a　single　type　of　resource　with　others　has　been　studied　in　the　literature.　In　reality,　a　system　may　require　different　types　of　resources.　For　example,　a　building　service　system　may　be　powered　by　electricity　(for　lighting)　and　gas　(for　heating).　However,　in　the　literature,　research　in　this　area　is　scarce.　This　paper　therefore　investigates　the　reliability　of　a　system　with　multiple　nodes.　Each　node　has　demand　requirement　for　two　types　of　resources,　which　can　be　shared　among　the　system　nodes　subject　to　their　bandwidths,　respectively.　In　addition,　the　resources　may　be　able　to　substitute　each　other.　This　paper　considers　both　unidirectional　and　bidirectional　substitutions.　The　system　is　said　failed　if　either　resource　supply　in　a　node　is　smaller　than　its　demand　even　after　performance　substitution　and　sharing.　A　universal　generating　function　technique　is　proposed　to　evaluate　the　system　reliability.　Numerical　examples　are　presented　to　illustrate　the　applicability　of　the　model.　The　influences　of　bandwidths　and　substitution　rates　on　system　reliability　are　also　discussed.