A novel multistage fluidized bed for dry desulfurization was presented for the improvement of a gas-solid flow structure. Experiments based on pressure signal acquisition were performed under extensive operating conditions. To obtain a systematic understanding of flow behaviors in the multistage fluidized bed, we applied nonlinear analysis methods coupled with wavelet decompositions. Some interesting phenomena were observed. The chaotic extent in the enlarged sections of the multistage fluidized bed is more sensitive to gas velocity than the solid circulating rate. In comparison with the traditional conveying section, change in flow behavior was observed in the enlarged section according to the Hurst analysis results. Particle movements including inter-particle, gas-particle and particle-wall dominate dynamic behaviors in the fluidized bed under examined operating conditions. The gas-solid interaction in the enlarged section was more intensive than that in the traditional conveying section. Dynamic comparisons between the lower and upper enlarged sections were also conducted. High similarities at the aspect of variation trend of dynamic characterizations were observed along the bed height of each section.