The fluidization of SiC cohesive particles of different sizes shows that (1) the fluidized characteristics is greatly affected by the size of particles, and the smaller the size of particles, the bigger the interparticle force, the worse the fluidized behavior; (2) SiC of average size larger than 10 mu m can be fluidized by increasing gas velocity, but SiC (5 mu m) cannot be fluidized. Particle agglomeration number Ae, which can be used to describe the fluidized behavior of particles is proposed based on interaction between the agglomerate body and the outer-most particles cohered. The calculation of particle agglomeration number Ae shows that cohesive particles can be fluidized if particle agglomeration number Ae less than or equal to 40 000. SiC5 may be fluidized with the method of adding particles, and optimum additive amount can be calculated by particle agglomeration number Ae.