A model for computing the trajectory of conducting particle from waste printed circuit board (PCB) scraps in corona electrostatic separator is established. Using analytical expression for computing non-uniformity of the electric field in the active zone of the separator and the differential method were used for computing the trajectories of conducting particles in the air, after detachment. The result shows that the trajectory of conducting particle can be computed under various initial parameters (R, r, L, alpha, U, n; p, r(0)) by the computing model and the computing results have a good agreement with the actual separating process. This model offers a possible for designing the new corona electrostatic separator. (C) 2007 Elsevier B.V. All rights reserved.