Gas insulated switchgear（GIS）encloses a complete set of switchgear such as circuit breakers

disconnector and busbars in a grounded metal enclosure filled with SF6 gas. However

the presence of foreign metal particles inside GIS can cause partial discharge and even dielectric breakdown. The movement characteristics of such two typical metal particles as linear and spherical particles in GIS under high voltage are studied. First

a partial discharge test platform is set up the discharge patterns of the two types of metal particles are tested. Then

the trajectories of different types of metal particles under different types of voltages are numerically simulated by the stress analysis of the metal particles. It is found by the numerical simulation results that there is certain law between the movement of the metal particles and its form under impulse voltage. It lays the foundation for setting up the relationship between the form and the trajectory of the metal particles under the impulse voltage and thus identifying a kind of images. The use of this image can perform shape and dimension assessment of the metal particles causing GIS fault. The study in this paper can provide reference for defining further the danger of the metal particles in the future.