Traditionally,　in　order　to　attract　more　travelers　to　use　the　public　transport　system,　planners　usually　pay　more　attention　to　the　feasibility　of　all　alternative　positions　to　choose　the　location　of　park　and　ride　(P&R)　facility,　but　it　is　found　that　they　also　ignore　some　important　factors.　In　this　article,　from　an　environmental　point　of　view,　we　try　to　model　the　P&R　facility＇s　site　selection　by　taking　both　demand　of　P&R　and　exhaust　emission　into　account.　This　model　will　be　a　good　reference　for　formulating　transport　policy　and　a　theoretical　support　for　green　transportation.　©　2010　ASCE.