Abstract: The power modules of multi-energy conversion equipment are prone to form creeping discharges at the interface of silicone gel and ceramic substrate. In this paper, the discharge characteristics of gel-solid insulation under high-frequency electrical stress, the development process of bubble injection and the damage characteristics of ceramic substrate are investigated. Based on the solid-liquid duality and self-healing of silicone gel, the problem of creeping discharge is transformed into a bubble development problem, and the failure law and damage mechanism of gel-solid insulation are explored. The study shows that the pulse signal of gel-solid creeping discharge is concentrated after the reversal of voltage polarity and near the peak, and the number and amplitude of discharge increase first and then decrease with the increase of frequency and increase monotonically with the increase of temperature. The different degassing methods reveal that the bubbles inside the silicone gel and the sintered air gap of the substrate are important factors affecting the creeping discharge. The damage of the substrate is related to the flow injection characteristics of the gel-solid interface and has a significant influence on the development of creeping discharge. The results can provide some reference for the design of IGBT package insulation structure.