Abstract: For the problem that the description about airflow field and droplet particle field of baffle defogger is not clear now, we established relevant mathematical model by the use of SST k-ω turbulence model and the two-phase flow theory. It carried out numeral simulation about baffled defogger three-dimensional airflow -droplet migration law. Simulation results show that the effect of the defogger is obvious, and the defogging rate is as high as 94.36%. Combined with the feature that the escaped dust wrapped in droplet form at wet dust-cleaning fan outlet, we proposed to install baffle defogger at wet dust-cleaning fan for defogging dust and conducted a field application. The results showed that the average removal rate of full dust and respirable dust increased from 84.3% and 80.4% to 96.6% and 91.3% after installed baffle defogger wet dust-cleaning fan. It is seen that baffle defogger applied to wet dust-cleaning fan works well and with good promotion prospects.