The invention relates to the technical field of silicone rubber, in particular to high-thermal-conductivity silicone rubber and a preparation process thereof. The high-thermal-conductivity silicone rubber is prepared from raw materials in parts by weight as follows: 80-120 parts of silica gel, 10-20 parts of vinyl silicone oil, 10-20 parts of filler, 10-20 parts of nano silicon, 8-12 parts of a reinforcing agent, 6-10 parts of naphthenic oil, 6-10 parts of a plasticizer, 4-8 parts of sulfur, 4-8 parts of an anti-ageing agent, 2-4 parts of a surfactant, 2-4 parts of bisphenol A, 1-2 parts of polyethylene, 1-2 parts of a lubricating agent and 0.5-1.5 parts of a cross-linking agent DCP. The thermal conduction pressure of the silicone rubber is uniformly dispersed, the thermal conduction performance is good, and the high-thermal-conductivity silicone rubber has better flatness and usability and can be applied to large-size, medium-size and small-size liquid crystal modules as a buffer and thermal insulation material.