Abstract: In view of the complex noise source distribution at steel plant, the ambient noise is very difficult to control.This paper analyzes the noise sources of the third hot-roll factory of Baosteel, which come from the fan of the dust-collecting equipmentt, he production line of the moto-board and silicon-steel, and the pressuring station of coal gas.The treatments for noise reduction are divided in two stages through taking the measures of noise eliminating, absorbing and insulating.Only a little effect appears after the first stage of treatments, and the noise values of the two typical measured points are all still beyond the standard value at night, that is 8 dB(A) for No.1 and 6 dB(A) for No.2 respectively.At the second stage, sound barriers are added to the pressuring station of coal gas, the production line of the moto-board and silicon-steel, as well as the transition area, as a result the noise values of the two measured points are all under 55dB(A) at night, which meet the factory standard.