Particle deposition under the influence of electrostatic force is modeled theoretically based on the semi-empirical (three-layer) model proposed previously (J. Aerosol. Sci. 31 (2000) 463). The electrostatic forces considered are the Coulombic force and the image force. Both Boltzmann and combined diffusion and field charging mechanisms are investigated. A modified Fick's law equation accounting for Brownian and turbulent diffusion, spatially-independent external forces, i.e. gravitational and Coulombic forces, and spatially-dependent external force, i.e. image force, is presented based on the simplified three-layer model. The results show that the concentration boundary layer thickness is very thin and the previous three-layer model can be further simplified. The Coulombic force influences the particle deposition significantly while the image force is important for high charge level particles in the presence of a weak electric field. The model predictions agree very well with the literature DNS results. (C) 2003 Elsevier Ltd. All rights reserved.