Abstract: A better insight into pressure signals could be helpful for the understanding of bubble behaviour as well as for the designing and manipulating of the gas-solid fluidized beds. Pressure fluctuations were measured in a rectangular fluidized bed with a height of 2.0m and a width of 0.3m by using a multi-channel pressure data acquisition system. Resin, belonging to Geldart B Group, was selected as experimental solid material. The characteristics of the pressure fluctuation were explored, and influences of superficial gas velocity and static bed height on the pressure fluctuation, pressure wave velocity and pressure fluctuation major frequency were investigated by using the standard deviation and the auto- and cross-correlation functions. The results show that the bubble behaviours such as formation, development, coalescence and break-up are major influence factors for the pressure fluctuation in the fluidized bed. The amplitude of pressure fluctuation near the interface between the dense phase and freeboard is governed by the bubble eruption. Pressure wave propagates within the bed and the pressure fluctuation signals along the bed height have obvious periodic characteristics in nature. Moreover, the pressure fluctuation, pressure wave velocity and main frequency are greatly dependent on the superficial gas velocity and the static bed height.