Abstract: The new vertical magnesia filling BTTZ production line is the current mainstream production line for this product, but due to the lack of compactness of the magnesia powder, it is difficult for its breakdown voltage to reach the 2 500 V standard.In view of the above shortcomings, the characteristics and influencing factors of magnesium oxide powder fall were studied by Finite Element Analysis, the falling powder fluid domain model was modeled by Ansys DesignModeler software, the simulation model were meshed by Ansys Mesh software.The material properties and boundary conditions of the model were set by Ansys Fluent software, and perform simulation calculation and post-processing analysis were carried out.Finally, the analysis results were obtained:under normal circumstances, the powder concentration in the edge part and the center point of the pipe was relatively large, while the powder concentration between the hollow circles (where the copper conductor was placed) was relatively small.In addition, the angle of the funnel had little effect on the uniformity of powder falling, while the particle size of magnesium oxide had a certain effect on the uniformity of powder falling.Within a certain range, the smaller the particle size, the more uniform the powder falling.Therefore, in order to improve the uniformity of falling powder, the particle size of the magnesium oxide powder could be appropriately reduced.