Electrostatic separation can be used to remove solid particles from fluid catalytic cracking slurry (FCCS). In this study, the electric field distribution, particle behavior and separation efficiency were investigated. Experimental studies covered the tests with separation efficiency given a set of parameters where the voltage was 13, 15, 17, 19, and 21 kV; the filler diameter was 9 mm; and the particle diameter was 2 pm. Simulation studies were conducted with experimental data including the electric field distribution; particle behavior and separation efficiency, where the particle diameter was 2, 5, and 10 pm; the voltage was 15 kV; and the filler diameter was 3 mm. The results showed that the electric field strength at the contact point was related to its position. To predict whether contact points could adsorb particles, an effective contact point model was presented and verified. Most particles were adsorbed at contact points by observing the trajectories of particles, which was consistent with theories. With an increase in the voltage and particle radius, the separation efficiency increased by 6.59% and 28.88%, respectively. The conclusions could be used as the theoretical basis for optimizing the device structure. (C) 2018 Elsevier B.V. All rights reserved.