Numerical simulation of the internal flow field in a new wet dust removal device for quick lime slaking is studied by the software FLUENT, with κ-ε turbulence model and SIMPLE algorithm. The results show that it is favorable for the dust removal to adopt tangential outlet, which can retard the escape of gas flow from the outlet, the best gas velocity is 15m/s, besides, when the number of nozzles is 3, the coverage area of mist droplets is largest, which makes dust particles and droplets contact fully, so it is beneficial to improve the efficiency of dust collection.