Granules polymers electrostatic behavior in a fluidized bed call be complicated by the differences in catalyst residue and Surface properties among them. Electrically charged particles cling together in large aggregates and adhere to the wall of the apparatus. Polymer particles with the same chemical composition but different sizes would have their own special contributions to the generation of static charges. It is improtant to understand polymer particles role oil electrostatic charge generation and dissipation. Experiments are carried out in a gas-solid fluidized bed with nitrogen as the fluidization gas to determine the relationship between the electrostatic charge level and the size of the polyethylene granule. By measuring the electrostatic potentials at different bed axial heights, it is found that the electric field inside the bed is significantly influenced by the size, weight fractions, and catalyst residue of added granular polyethylene. Consequently, ail impact factor of granules (F-b) is proposed to Study the influence of particle size and the weight percent of the residual catalyst to the electrostatic potentials. And it is found that the greater the degree of fineness of the granules, the more percentage of the residual catalyst in the particles, which results in the stronger affect oil the electrostatic behavior in the fluidized bed.