Fluidization is a process of wide application, but its dynamic behavior is not well understood because of its multi-scale heterogeneity and regime multiplicity which are difficult to simulate in traditional numerical methods. By discretizing the fluid phase into a large number of interactive simple particles, which can incorporate many-body moving boundaries easily, pseudo-particle modeling (PPM) has reproduced reasonable radial and axial heterogeneity on macro-scale as well as solids clustering and fluid flows on meso- and micro-scales. The simulation suggests a consistent evolution of the complexity across different scales with itself serving as an ideal exploring tool.