Dry dedusting process("LT"system)has been applied in the flue gas purification and recovery of steelmarking plant of Jinan iron and steel group Co., Ltd. Axial flow fan is an important facility in this system, and the power source for the gas of the converter. This article makes a detailed description about the method and principle of the wind-amount control in axial fan system. It analyses the reason of difference between wind-amount in theory calculated and real from converter when steelmaking, and talks about how to solve this problem, via optimizing the parameters of wind-amount control model, to reduce the energy consumption, and also to avoids the water amount offset, the too wet dust and so on, which ensure the stable running of the LT system .