In order to make the direct air-cooling units operate safely in summer and ensure the units output,the spray cooling devices are used in many direct air-cooling units,so which can improve the capability of the direct air-cooling units operating safely in summer.The control system of the traditional spray cooling system is too simple,which caused the waste of the lots of desalted water,and increased the cost of the units energy consumption.Through discussing the control system of spray cooling devices puts forward the reasonable control methods.