The invention discloses an exhaust gas recirculation (EGR) system. The EGR system comprises an EGR valve gas-intake adapter pipe, an EGR valve gas-exhaust pipe, an EGR valve and an EGR valve temperature control valve, wherein the outer end of the EGR valve gas-intake adapter pipe is fixedly mounted in an EGR outlet of an engine gas-exhaust pipe; the outer end of the EGR valve gas-exhaust pipe is connected with an EGR inlet of an engine gas-intake pipe through an EGR valve gas-exhaust adapter pipe; the EGR valve is fixed to the inner end of the EGR valve gas-intake adapter pipe and the inner end of the EGR valve gas-exhaust pipe, and the EGR valve is connected to the interior of the engine gas-intake pipe through a positive pressure gas-intake hose; the EGR valve temperature control valve is arranged on the positive pressure gas-intake hose and an engine water-draining header pipe; the EGR valve and the EGR valve temperature control valve are in a closed state on normal circumstances. According to the EGR system, temperature of exhaust gas is decreased by air cooling, the EGR valve is opened through gas-intake positive pressure and water temperature of an engine, so that the national emission rules are followed while the valve is effectively opened in an electric-control common-rail diesel engine.