Abstract: In this paper,for the insulation failure caused by particles in AC environmentally friendly gas insulated transmission line（GIL）, a scaled experimental platform was built, using aluminum powder and silicon powder to simulate the metal and semiconductor dust particles that may be introduced in the GIL. Ultrasonic signal and image of particle motion were recorded. The distribution of dust particles in the cavity was obtained. The force model of dust particles in the cavity was established, and the different distributions of the two particles were revealed. Studies have shown that dust particles with a smaller particle size are subjected to Van der Waals forces in the cavity, and semiconductor particles adhere to the surface of the insulator due to different charge dissipation mechanisms. According to the distribution characteristics of the particles, this paper designed two types of traps, grid trap and strip trap. According to the trap capture coefficient, the particle trap setting proposal was proposed. The grid trap was set at the end of the chamber and the strip trap was set on the other parts of the chamber. This combination can achieve the optimal capture effect.