Urban　metro　signal　system　is　a　complex　system　to　guarantee　the　safe　and　efficient　running　of　urban　metro　vehicle,　of　which　any　equipment　malfunction　could　induce　danger.　In　the　actual　operation,　the　degraded　mode　of　signal　system　is　generally　used　to　organize　urban　rail　transit　vehicle　when　the　signal　system　work　abnormally.　The　traditional　degraded　mode　of　urban　rail　transit　signal　system　is　telephone　occlusion　method,　which　cannot　meet　the　demand　of　a　large　amount　of　passengers＇　evacuation　for　its　low　efficiency　in　organizing　vehicles.　In　China,　route　occlusion,　a　novel　degraded　mode,　is　proposed　by　a　few　urban　rail　transit　companies　to　improve　the　efficiency　of　transport　in　abnormal　situation　and　further　ensure　rapid　evacuation.　This　paper　comparatively　analyzes　the　capability　of　telephone　occlusion　and　route　occlusion　to　accommodate　rail　vehicles　in　an　interval　between　two　depots　in　the　same　scene.　This　paper,　furthermore,　models　and　analyzes　telephone　occlusion　method　and　route　occlusion　method　using　Petri　net　in　view　of　its　unique　advantage　to　describe　asynchronous　and　concurrent　system.　Finally,　an　example　of　Chang　Ping　line　of　Beijing　metro　is　particularized　to　explain　the　different　efficiency　to　organize　trains　in　degraded　mode　of　urban　rail　transit　signal　system.　Copyright　©　2015　by　KSI　Research　Inc.　and　Knowledge　Systems　Institute　Graduate　School.