Abstract: In a fluidized bed with a high static bed height of 800mm and an inner diameter of 90mm, axial pressure fluctuations are measured at different gas velocities in a vibrated fluidized bed (VFB) and a non-vibrated fluidized bed. The noises in the signals are filtered by wavelet transform. The characteristics of the pressure fluctuations in the VFB and the non-vibrated fluidized bed are analyzed by using chaotic theory. It is shown that the correlation dimension and Kolmogorov entropy can be used to characterize the fluidization state in the VFB. There is a jet regime near the air distributor of the VFB, in which the pressure fluctuations are chaotic. When gas velocity is near the minimum bubbling velocity, the correlation dimension and Kolmogorov entropy of the pressure fluctuations in the jet fluidization region reach the minimum. At lower or higher gas velocities, the values of the correlation dimension and Kolmogorov entropy are high due to the particles’ or bubbles’ random disturbance on pressure fluctuation. Above the jet fluidization region, the formation and coalition of bubbles are restrained due to the shear effect of vibration wave on the bed. The fluidization in the main part of the VFB is homogenous. In this region,pressure fluctuation is periodic. The correlation dimension is in the range of 1—1.5.Kolmogorov entropy approaches to zero.