Abstract: Intermittency means the occurrence of a signal that alternates randomly between long regular phases and relatively short irregular bursts.In this paper,we simplify the mathematical analysis of pressure signal by idealizing it as a train of signals of zero duration and of size unity in a bubbling fluidized bed,0.30m in diameter and 3.8m in height.Therefore,the simplified signals are zero corresponding to the laminar signals and unity corresponding to irregular bursts.Statistics show that mean laminar length decays with excess gas flow above u mf ,obeying a power law < l > ∝(u-u _mf ) ^-0.55 .Similar results were obtained by Daw et al (1995) .These results suggest that laminar motion is disturbal more frequently and chaotic burst occurs more frequently as gas velocity increases,and chaotic nature of Type-Ⅰ intermittency of fluidizing systems is confirmed further.The chaotic irregular bursts can be considered as the result of intermittent gas bubbles in fluidized beds.