The invention provides a diesel engine EGR (Exhaust Gas Recirculation) system having a humidification effect. The diesel engine EGR system having the humidification effect comprises a diesel engine and a turbocharger; a gas compressor of the turbocharger is installed on an air inlet pipe of the diesel engine; a turbine of the turbocharger is installed on an exhaust pipe of the diesel engine; an air inlet pipe portion which is arranged between the gas compressor and the diesel engine is sequentially provided with an intercooler and a venturi pipe; an exhaust pipe portion which is arranged between the turbine and the diesel engine is communicated with an EGR pipeline in a side mode; the EGR pipeline is communicated with the venturi pipe; a filter screen, an EGR cooler, a spraying chamber and an EGR valve are sequentially installed on the EGR pipeline from the exhaust pipe to the venturi pipe; the EGR cooler which adopts water cooling is provided with a water inlet pipe and a water return pipe; the water return pipe is communicated with the spraying chamber; a water spraying valve is installed on a pipeline between the water return pipe and the spraying chamber. The diesel engine EGR system having the humidification effect can achieve EGR and humidification of inlet air and overcomes the disadvantages when a conventional EGR system and an air inlet humidification system operate in a combined mode.