Based　on　the　field　investigation　and　data　analysis,　this　study　identifies　the　general　traffic　problems　in　the　old　downtown　areas　that　the　county　cities　are　facing.　These　issues　include　the　concentrated　traffic　demand　and　the　unreasonable　regional　traffic　organization,　as　well　as　the　inadequate　traffic　facilities　or　parking　lots,　and　the　disorder　of　traffic　system.　Focusing　on　the　actual　problems　of　Chengde,　a　county　city　in　north　China,　the　paper　proposes　feasible　methods　and　plans　of　engineering　optimization　design　for　the　downtown　area　traffic.　This　design　is　optimal　when　the　road　space　and　traffic　facilities　are　limited.　It　implements　three　of　the　following　strategies　including　the　regional　traffic　organization　optimization,　modification　of　key　intersections　and　reconstruction　of　major　road　segments.　Finally,　the　study　establishes　an　optimization　design　methodology　and　provides　possible　countermeasures　to　upgrade　the　transport　systems　of　old　downtown　area　of　county　cities.　©　2012　American　Society　of　Civil　Engineering.