In view of the low temperature of flue gas after the existing wet and semi-dry desulfurization methods, which cannot meet the requirement that flue gas exhaust temperature of blast furnace hot blast stove should keep above 140 ℃, a calcium-based dry desulfurizer is prepared, and based on this, a desulfurization test device is constructed in the iron-making plant, and the relationship among bed height, flue gas flow rate, temperature and desulfurization efficiency is studied, and through the relationship among operation time and desulfurization and dust removal efficiency, the best refueling cycle is obtained. The test results show that: the desulfurization efficiency is increased with the increase of bed height, and the optimal bed height is 2 m; the desulfurization efficiency is decreased with the increase of flue gas flow rate in empty tower, and the optimal flue gas flow rate in empty tower is 0.5 m/s; the desulfurization efficiency is 80.0%～87.9% when the flue gas temperature is 150～250 ℃, which is not greatly affected by temperature. The desulfurizer reloading cycle is 20 d, and the reloading cycle bed height is 1 m. During the reloading cycle, the SO₂ and particulate mass concentrations meet the ultra-low emission requirements. At the initial stage, the linear regression equation between the bed resistance P and the empty tower flue gas flow rate u is: P=3400u-693,R²=0.9927, which can be used for the bed resistance calculation. The bed resistance increases in the later stage, the actual bed resistance should be enlarged by 1.55 times as a correction to provide a calculation basis for the full pressure selection of the desulfurization fan. Finally, the main components of by-products are measured and four comprehensive utilization paths for by-products are proposed.