based on experimental test-bed of blast furnace slag waste heat recovery, the paper studied on the changes of the key parameters such as blast furnace slag discharged temperature, the speed of the granulation device, which impacted on the results of particle diameter distribution and sphericity coefficient, so as to master the best operating parameters of the blast furnace slag dry centrifugal granulation, and to provide a experimental basis for blast furnace slag waste heat recovery. The results showed that: when the discharged temperature of the blast furnace slag is controlled in 1400-1450 ° C , and the speed of the granulation device is controlled above 2000r/min, there is a good sphericity of the blast furnace slag, and there is up to 80% particle diameter distribution of 2-5mm.