With　the　increase　of　passenger　flow　pressures,　metropolises　reduce　traffic　pressure　by　adding　new　lines.　To　ensure　the　rationality　of　new　lines,　it　is　necessary　to　analyze　the　impact　of　different　line　types　on　the　vulnerability　of　the　existing　rail　transit　network　(RTN).　Firstly,　the　new　lines　are　divided　into　several　types.　Then,　the　models　of　different　line　types　connected　to　the　rail　transit　network　are　established　by　the　L-space　method.　Moreover,　a　new　method　that　comprehensively　evaluates　the　rail　transit　network　vulnerability　based　on　the　index　of　average　shortest　path　length,　network　efficiency,　and　average　node　betweenness　is　proposed.　Finally,　taking　Beijing　as　an　example,　obtain　the　influence　characteristics　on　the　vulnerability　of　Beijing　rail　transit　network　(BRTN)　connected　with　different　line　types.　The　results　show　that　the　ring　line　can　effectively　reduce　the　vulnerability　of　the　network　compared　with　a　penetrating　line　and　outskirts　extension　line.