In　response　to　challenges　caused　by　high　gasoline　prices,　traffic　congestion,　and　greenhouse　gas　emissions,　smart　internment　on　intercity　rail　transit　infrastructures　and　service　suggests　a　rekindling　of　many　countries’　interest　in　offering　a　range　of　benefits　over　automobile　travels.　In　order　to　check　the　suitability　of　the　proposed　intercity　rail　transit　system　with　the　local　conditions　in　a　region,　models　for　relating　the　intercity　rail　transit　scope　and　social　economy　factors　have　been　developed　with　the　datasets　obtained　in　the　Pearl　River　Delta　(PRD)　region　in　Guangdong　Province,　China.　In　this　paper,　the　accessibility-based　approach　is　presented　to　explore　the　impact　of　the　intercity　rail　transit　system　planning　on　the　regional　development.　The　impact　of　three　typical　accessibility　variables,　transportation,　population,　and　economic　accessibilities,　are　considered　in　the　approach.　The　global　rail　transit　scope　planning　models　are　developed　by　using　the　regression　technique　to　correlate　the　lengths　of　254　regional　intercity　rail　transit　systems　in　different　countries　in　the　world　with　social　economy　factors.　Those　models　are　used　for　estimating　the　intercity　rail　transit　size　for　the　PRD　region.　The　modeled　transit　scopes　are　examined　with　spatial　distributions　of　the　defined　three　accessibilities　at　each　node　(or　centroid　center　of　a　town)　in　a　Geographic　Information　System　environment.　The　developed　method　has　been　proven　helpful　to　understanding　the　gap　between　transport　supply　and　potential　travel　demand　and　the　suitability　of　each　node　to　alignment　of　each　rail　transit　route　through　the　PRD　region　case　study.　©　2017,　The　Author(s).