There is still an interest in improving electrostatic precipitator (ESP) collection Of fine particles (micron and submicron sizes). However, it is not yet clear whether the turbulent flow patterns caused by the presence of electric field and charge in ESPs advance or deteriorate fine particle precipitation process. In this paper results of the Particle Image Velocimetry (PIV) measurements of the particle flow velocity field in a wire-to-plate type ESP model with seven wire electrodes are presented. The PIV measurements clearly confirmed formation of the secondary flow (velocity of several tens of cm/s) in the ESP model, which interacts with the primary flow. The particle flow pattern changes caused by the strong interaction between the primary and secondary flows are more pronounced for higher operating voltage (higher electrohydrodynamic number NEHD) and lower primary flow velocity (lower Reynolds number Re).