Residence and contact time distribution functions of the fluidizing gases in the column was obtained, using the two parallely connected fluidized beds of equal size, gases and solid particles are able to be mixed through the open hole of the vertically intersecting wall. Comparing the experimental and the theoretical curve, it was found that the influence of the piston flow with a diffusion based on the complete mixing model, acted upon the residence time distribution function. From this results, it was delivered that fluidizing solid particles and gases, when reduced time, φ>0.5, were made up complete mixing about 90% So these facts are confidence of theoretical equation is obtained by author`s complete mixing model, will be available for the design of catalystic fluidized equipment.