The　analysis　process　of　the　overall　reliability　evaluation　model　of　the　traditional　photovoltaic　power　generation　system　is　complicated,　and　the　shortcomings　of　the　system　weak　link　cannot　be　analyzed.　This　paper　proposes　a　fuzzy　hierarchical　evaluation　method　based　on　sensitivity　analysis　to　evaluate　the　reliability　of　photovoltaic　power　generation　systems.　The　method　judges　the　whole　system　failure　factor　by　introducing　the　fault　frequency,　the　degree　of　fault　impact,　and　the　second　evaluation　criterion　of　the　fault　detection　difficulty.　In　particular,　the　Monte　Carlo-based　component　sensitivity　analysis　method　is　used　to　calculate　the　degree　of　fault　impact.　Finally,　the　method　of　this　paper　is　used　to　analyze　a　photovoltaic　power　generation　system.　The　effectiveness　of　the　proposed　method　is　verified　by　the　overall　reliability　analysis　and　the　evaluation　of　fault　factors.　It　is　proved　that　the　method　is　of　great　significance　for　analyzing　the　reliability　of　the　photovoltaic　system　and　the　weak　link　of　the　system.　©　2019　IEEE.