By using Computational Fluid Dynamics (CFD) method,numerical simulation of gas flow distribution of ESP transform to baghouse in cement kiln head of 6000 t/d production. Through numerically simulation,air volume of every filter bag cell and head-on gas flow velocity distribution of filter bag were displayed. By adjusting the configuration parameter of the gas flow distribution device during the numerical simulation, it gives the result that the manner of installing gas flow distribution device, when the windage of the air volume of every filter bag cell is not more than 5% and the press drop of the dust collector with clean filter bag is 300 Pa. The calculated results showed good agreement with the measured results in the field. The simulation results were carried out by transformation. The dust emission concentration of precipitator is 26.6 mg/m3, and the dust running resistance is less than 1000Pa, can achieve the performance assessment requirements.