Purpose　-　To　establish　a　stimulating　traffic　model　of　ring　road　systems　and　study　the　traffic　effects　of　ring　road　in　the　center　of　a　large　city,　including　the　influence　in　vehicle＇s　travel　time　and　distance.　Design/methodology/approach　-　Different　from　the　ring　road　systems　in　the　west,　Beijing　and　other　big　cities　in　China　build　ring　roads　in　city　center.　However,　it　seems　that　those　systems　do　not　work　because　the　traffic　problem　still　exists　when　the　number　of　cars　in　the　city　increased　quickly　in　past　five　years.　According　to　the　real　geographic　topology　network　structure　around　Er　Huan　road　in　Beijing　city　center,　a　simplified　simulated　traffic　model　was　built.　Then,　two　indices　of　traffic　effects,　average　travel　time　and　path　length　were　studied　by　comparing　the　two　models　with　or　without　ring　road.　Findings　-　According　to　the　simulation,　although　a　high-speed　ring　road　shortens　the　travel　time,　it　isolates　the　nature　road　network　system　and　increases　travel　distance　in　the　city　center.　Furthermore,　it　is　uneconomic　building　a　ring　road　to　relieve　traffic　jams.　Research　dmitations/implications　-　Only　Er　Huan　road　in　Beijing　traffic　system　was　simulated　in　the　model.　A　more　complicated　ring　road　system　needs　to　be　developed.　Practical　implications　-　A　useful　model　for　optimizing　traffic　system　with　ring　roads,　and　providing　a　support　for　doubting　the　strategy　of　developing　ring　road　in　city　center　district　in　many　cities　of　China.　Originality/value　-　This　is　a　new　way　by　establishing　the　simulation　model　to　analyze　the　scheme　of　ring　road　traffic　systems.　Furthermore,　advice　for　current　situation　are　concluded　and　it　is　useful　for　optimizing　current　traffic　system.