In the present work, hydrodynamic characteristics viz, pressure drop and top packed bed of a co-current gas-liquid-solid semi-fluidized bed have been studied using liquid as continuous phase and gas as discrete phase. Experiments have been conducted in a 100 mm ID, 1.8 m height vertical perspex column using air, water and lime stone in order to develop a good understanding of each flow regime in gas-liquid-solid semi-fluidization. It is observed that pressure drop increases with increase in particle size, expansion ratio and superficial gas velocity. The minimum liquid semi-fluidization velocity increases with particle size and bed expansion ratio but decreases with superficial gas velocity. The height of top backed bed decreases with particle size but increases with liquid and gas velocities.