The　power　transfer　systems　(PTS)　has　special　reliability　properties,　including　multiple　states　and　fault　dependence.　Consequently　traditional　binary-state　reliability　modeling　methods　cannot　accurately　evaluate　the　reliability　of　PTS.　In　older　to　resolve　the　contradiction　between　terminal　energy　demand　and　power　transfer　capability　of　PTS,　this　paper　proposes　a　novel　multi-state　reliability　model　based　on　power　transfer　efficiency　(PTE)　for　reliability　evaluation　of　PTS.　The　multi-state　model　caused　by　performance　degradation　based　on　PTE　is　considered　in　this　paper:　In　addition,　the　failure　correlation　in　virtue　of　the　system　structure　and　energy　allocation　mechanism　is　analyzed　in　the　proposed　model,　and　the　corresponding　reliability　evaluation　result　is　obtained　under　different　terminal　energy　requirements.　The　approach　is　verified　on　the　example　of　a　dual　hydraulic　actuation　system　(DHAS),　in　which　the　stochastic　model　based　on　the　generalized　stochastic　Petri　nets　(GSPNs)　is　established　and　combined　with　the　power　transfer　capability　via　universal　generating　function　(UGF).　Though　changing　flow　rate　to　face　the　degradation　rate　of　hydraulic　pump,　the　reliability　assessment　of　DHAS　based　on　the　proposed　reliability　model　is　effective　and　accurate.