Abstract: From the field operation of AC GIS in recent years, it is found that fiber can also cause equipment insulation failure. Under DC unipolar field, the charging of fiber is more sufficient, the movement will be more active, and there is a strong interaction with the surface charge of insulator. In this paper, by building a semi-enclosed coaxial cylindrical electrode experimental platform, the charging effect of fibers on the electrode under DC voltage and the adsorption motion characteristics near the basin insulator are studied. Finally, the dust figure method is used to analyze the degree of influence on the surface charge accumulation of the insulator under the fiber attachment state. The results of the study show that the fiber exhibits time-lag characteristics due to the charging effect, and the charging characteristics of the fiber are verified experimentally. After the fiber lifts, it presents oscillating upward adsorption motion in the air gap. When the fiber length is long or it is far away from the insulator, the radial velocity after lifts is small, so the movement height is very low due to the influence of the electrostatic adsorption of the ground electrode, and then attach to the upper part of the insulation. On the contrary, the radial velocity after the fiber lifts is large, and it is attached to the lower part of the insulation. When it collides with the surface of the insulator for the first time, it climbs or bounces, and is finally adsorbed on the upper surface of the insulator. According to the dust map, after the long-term withstand voltage in the attached state of the fiber, it will show an "umbrella" charge distribution. When the fiber is in contact with the high-voltage electrode, the charge distribution is wide and the accumulation is the largest; the second is in contact with the ground electrode; it is the smallest when it is attached to the middle part of the insulator.