Abstract: The effects of the operation parameters, such as pulse amplitude, pulse frequency, fluid velocity and flow ratio, and structure parameters, such as packing free ratio and packing distance, on the hydrodynamics, including the flooding rate, flooding holdup and holdup of dispersed phase, of φ50 pulsed extraction column with discs and doughnuts were experimentally studied for the 30% trialkyl phoshine oxide (TRPO)(in kerosene)/1 mol·L^-1 nitric acid/water system.Experimental results indicated that the flooding rate increased with increasing packing free ratio and decreasing pulse strength, and was independent of packing distance.Based on the results of the flooding holdup, the optimal packing free ratio of 23% was suggested.The holdup of dispersed phase is directly proportional to the velocity of continuous phase, flow ratio and pulse amplitude, but independent of pulse frequency.The wetting of packed materials led to the different effects of packing distance on the holdup of dispersed phase for 30% TRPO (in kerosene) or 1 mol·L^-1nitric acid as the continuous phase.