This paper presents a Computational Fluid Dynamics (CFD) model for particle trajectory inside a wire-plate electrostatic precipitator (ESP). The turbulent gas flow and the particlemotion under electrostatic forces were modelled using CFD code ‘FLUENT’. Reynolds averaged Navier-Stokes equations were solved numerically for predicting the gas flow. The turbulence was modelled using the realizable k-ε turbulence model. The effect of electric field had been captured by adding a source term in the momentum equation. This additional source term was obtained by solving a coupled system of the electric field and charge transport equations. The particle phase was simulated by using Discrete Phase Model (DPM). The results of the simulation showed that particle trajectory depends on the size of the particle diameter. The larger the diameter, the more efficient was the particle collection due to the higher particle charging. This study gives an insight into the particle dynamics and its collection inside any industrial ESP.