To explore the characteristics of staged fluidization caused by segregation in the fluidization process of iron ore powder with Geldart-B particles, the experimental study on bubbling fluidization of iron ore powder with average particle size of 350 μm was carried out in a two-dimensional fluidized bed reactor. The characteristics of staged fluidization of bubbling fluidization of iron ore powder with single particle size distribution were obtained, and the causes of staged fluidization were explained in combination with the pulverization effect. Then, a staged fluidization experiment was carried out on a three-component glass bead system. The standard deviation of bed pressure drop was used to identify the staged fluidization process. Finally, the bubble behavior characteristics of glass beads and iron ore powder systems with the same average particle size in different fluidization stages were compared. The results show that the pulverization effect of iron ore powder in the fluidization process will lead to an increase in the standard deviation of particle size distribution. The particle segregation in the fluidization process leads to different bubble behavior characteristics, which makes the bed show staged fluidization characteristics. Combined with the characteristics of staged fluidization and the standard deviation of bed pressure drop, it is found that the bubble behavior in different fluidization stages leads to the change of standard deviation, and the standard deviation of bed pressure drop in stable fluidization stage tends to be fixed. The pulverization effect in the fluidization process of ore powder leads to the increase of the standard deviation of particle size distribution. In the stable fluidization stage, the average equivalent diameter of bubbles increases, and the longitudinal velocity and transverse velocity of bubbles also increase.