Aiming at the problems of complicated implementation process and poor timeliness of current sintering cooler air leakage rate measurement methods, the dual - system coupling balance method is provided to measure the air leakage rate of sintering cooler. Specific methods: 1) According to the characteristics of the mutual coupling of the waste heat boiler and the cooler, a dual - system model of the waste heat boiler and the cooler is established; 2) The heat balance model of the waste heat boiler is used to calculate the flow of flue gas into the boiler, that is, the flow at the coupling point, and then the air leakage rate is calculated by using the mass balance model of cooler system according to this flow. This method is applied to a 360 m² air leakage rate test with a cooler in a steel plant, and the average air leakage rate tested is 47.5%. The results show that the new method can calculate the online air leakage rate conveniently and fastly, which overcomes the shortcomings of the traditional method of measurement difficulty and poor timeliness.