Bed porosity and heat transfer characteristics have been investigated in a liquid-liquid-solid fluidized bed(0.102 I.D.×2.5m in height). Effect of velocities of dispersed and continuous liquid phases and particle size on the bed porosity and heat transfer coefficient in the bed have been determined. Water and kerosene have been used as a continuous and a dispersed liquid phase, respectively. Glass beads whose diameter are either 1.0, 2.1, 3.0 or 6.0 mm have been used as a fluidized solid phase. It has been found that the heat transfer coefficient and bed porosity have increased in the beds of relatively large particles(dp≥3.0 mm), but they have attained their local minima in the beds of relatively small particles(dp≤2.1 mm), with increasing the dispersed liquid velocity. The heat transfer coefficient has increased with increasing the particle size, however, it has exhibited the local maximum with increases in the continuous liquid velocity and bed porosity. The heat transfer coefficient has been well correlated in terms of Nusselt number and dimensionless velocity and scale of micro-eddy based on the isotropic turbulence theory.