Abstract: The fluidization mechanism of group C powder under an external magnetic field has been studied.Magnetic powders rearrange themselves to form the“structure of chain”with these chains being able to penetrate into bubble from the top and make bubble broken,which is the reason why magnetic field can improve fluidization quality of group C powder.A mathematical model is derived through the forces analysis of chains.Furthermore,a dimensionless number is developed to forecast the formation of magnetically condensed state in this paper.