In order to achieve the goal of carbon peaking and carbon neutrality while taking into account the product yields of both gasoline and polyolefin, it is desirable to further optimize the polyolefin catalytic cracking technique by introducing two types of catalysts with distinct physical properties into the one reaction-regeneration system. Therefore, this work focuses on the flow and mixing characteristics of the binary particle system in a fluidized bed. The axial distribution of pressure in the binary particles fluidized bed was measured. The average solid concentration in the axial direction was investigated consequentially. The variation of the interface location between the dense phase and dilute phase zones was determined by analyzing the turning point of the axial profile of the differential pressure. An empirical coorelation was given based on the experimental results. Furthermore, the relationship of the fluidization performance of the binary particles in the fluidized bed to the gas velocity as well as the particle mixing ratio were discussed by investigating the standard deviation of pressure signal. The experimental results showed that the average particle concentration tended to decrease in the axial direction of the fluidized bed. The particle concentration decreased with an increasing of the superficial gas velocity in the dense-phase zone whereas it presented an increasing tendency in the dilute phase zone. The total average particle concentration in the dense-phase zone assumed a maximal value when the mixing ratio of big particle in the binary particles was 0.685. The interface height between the dense-phase and the dilute phase zones increased with an increasing of superficial gas velocity. It was also found that the fluidization performance and mixing degree of binary particles in the fluidized bed reached the best when 0.225≤xl≤0.479 and 0.561≤ug≤1.122 m/s.