Based on an analysis of the combined effects of centrifugal and electrostatic separation, a revised equilibrium-path model for the electrostatic-cyclone dust collector is established in the paper. With this semi-empirical model the effects of centrifugal and electrostatic separation on the performance of electrostatic cyclone are illustrated. Using the experimental facility for dust collectors, experimental investigations on the performance of electrostatic cyclone are carried out systematically. Effects of the gas-stream inlet velocity at entrance of cyclone, the operating voltage and the configurations of discharge electrodes, etc. on the performance of dust collector are studied in detail.