Abstract: Purification and recovery of dense medium by magnetic separation,which plays a key role in maintain the density stability of the fluidized bed and continuous separation,is one of important process in air dense medium fluidized bed coal beneficiation.On the basis of size properties requirements of fluidized magnetite powder used as dense medium in air dense medium separation,through comparative analytical method influencing factors of magnetite powder and magnetic separation process were evaluated from the respective of the parameters such magnetic susceptibility,particle size,density and so on,which have an effect on purification and recovery of magnetite powder by dry magnetic separation.And moisture of magnetite powder in dry magnetic separation was discussed.Then the problems of being paid more attention to in dry magnetic separation were presented such as moisture,size,content,used conditions and so on.The results show that differences in magnetic susceptibility,particle size and density between magnetite powder and fine coal,this provides advantages in magnetic separation.Application feasibility of purifying and recovering magnetite powder by dry magnetic separation is feasible with being controlled moisture.There must choose or design suitable magnetic separator and simultaneously carried out more research to determine the optimum operating parameters.