Abstract: The twin-plane 12-electrode ECT(Electrical Capacitance Tomography) from Process Tomography Limited (UK) was employed to investigate the effect of different gas spargers on bubble behavior in a bubble column. The gas holdup increases with the increase of the number of orifices in the sparger and the superficial gas velocity. When the sparger has a bubble cap, the gas holdup becomes high. The quasi-3d flow structure of bubbles was observed using Plot3d which showed that the bubbles perform a spiral motion along the wall.