Granulation procedure was carried out in a 0.109m I.D., 1.8m height fluidized bed coal combustor of the multi-sized particles. The domestic anthracite with heating value 3240㎉/㎏ was used. Granulation of fine coal particles and fluidizing characteristics were investigated by the pressure fluctuation properties such as mean pressure, standard deviation of pressure fluctuation and power spectrum distribution. Defluidization state and granulation mechanism were also studied by the various analysis. It was found that the conversion efficiency in the elutriated stream was increased by the coalescence of fine coal particles. Defluidization and pressure fluctuation properties were interrelated and this result was indication of the capabilities of pressure fluctuation properties analysis in the diagnostics of fluidizing state.