A fuel reforming system for a vehicle intake and exhaust line that reforms fuel in a vehicle intake and exhaust line including an exhaust gas recirculation (EGR) apparatus that recirculates a portion of an exhaust gas of an engine and a recirculation line that transfers an exhaust gas that is recirculated by the exhaust gas recirculation apparatus to supply as an intake gas of the engine, may include a fuel reformer that mixes an exhaust gas that passes through the recirculation line with fuel and that reforms fuel that is mixed in the exhaust gas, wherein an insulation material is coated at a wall surface of the fuel reformer.