The electrostatic force caused by human walking and its effect on particle detachment and resuspension is studied using a capacitor theory. The shoe-floor system is treated as a plate capacitor. The electrostatic charges and the electric field strength generated by the tribology charging at shoe-floor contact are estimated by the capacitor theory. The Coulomb force, image force, dielectrophoretic force and polarization force are evaluated in the study. The foot stepping down and up processes are treated as the motion of an effective circular disk toward or away from a stationary surface. The surface roughness, the adhesion and drag forces exerted on the particles are also included in the study. The critical radii, particle concentration and resuspension rate under various conditions are estimated.