In this paper

1%，2%，3%，4%，5%，6% and 7% nano-silicon carbide/silicone rubber composites are prepared，and the dielectric spectroscopy properties of the composites are measured by broadband dielectric spectroscopy tester. The results show that，at room temperature，the permittivity of the composites increaseswith the increase of silicon carbide content at all test frequency，and at the frequency of below 1 Hz，it is less thanthat of pure silicone rubber. The tan$ of the composites decrease with the increase of silicon carbide content at thefrequency of below SOHz，and increase with the increase of silicon carbide content at the frequency of above 1 kHz.The AC breakdown behavior of different loading of the composites is investigated. It can be found that with the in-crease of silicon carbide content，the breakdown strength of composites increases first and then decreases. Whenthe silicon carbide content is 3wt%，the breakdown strength of the composites reaches its maximum value.