Abstract: In order to well know the outlet location of the air duct affected to the concentration distribution of the hydrogen sulfide in the fully mechanized driving face, based on the turbulent flow k-ε equation and the dynamic dispersion equation, a mathematical model of the hydrogen sulfide migration and diffusion was established. The COMSOL Multiphysics software was applie to the simulation on the distribution law of the hydrogen sulfide in the fully-mechanized driving face under different location of the air duct. The results showed that when the air duct had a distance of 3 m to the driving face, the hydrogen sulfide concentration in the turbulent flow area closed to the driving face was minimum and at the low corner below the air returning side, the hydrogen sulfide diffusion scope was minimum. Based on the optimized location of the air duct, an optimization was conducted on the layout of the external spray in No.10102 fully-mechanized driving face of Baozigou Mine. The practices showed that when the distance of the air duct to the driving face was 3 m, the hydrogen sulfide concentration reduced by 6.3% in comparison with the previous location. After the spray device optimized, the purification efficiency of the hydrogen sulfide further improved by 6.2% and the comprehensive control efficiency reached to 95.6% and could be favorable to the hydrogen sulfide dilution and centralized purification.