In order to suppress the obvious infrared radiation characteristics of ship engine’s exhaust gas,a two-stage spray cooling experiment was done.Experimental results show that two-stage spray cooling makes gas temperature decrease obviously.When the first spray pressure and the second spray pressure are at the best spray pressure respectively,the gas temperature under any condition can be controlled within the range from 330 K to 360 K.The models of the best spray pressure and the flow rate of the two stage sprays are obtained by experiments.The respond time of the gas temperature tending to the stable value after spraying is obtained,and the suggestion of adjusting the spray working condition is given based on respond time when the engine working condition changes.The research can provide data and referable models for suppressing the infrared radiation characteristics of ship engine exhaust gas system.