Geothermal energy is a kind of clean and renewable energy， and replacing high carbon energy with geothermal energy is one of the effective ways to reduce carbon emission. Underground pipe insulation technology is one of the key technologies that influence efficiency of geothermal energy exploitation. This paper describes the development situation of underground thermal insulation pipe in terms of the structure， pipe materials， insulation materials， and production process； and points out that the blend of nano insulation materials and vacuum pipe will be the development trend in the future with vacuum nano insulated pipe as the first choice for deep geothermal energy exploitation； meanwhile， it is pointed out that research should be focused on the influence mechanism of basic structure factors on thermal insulation performance of vacuum nano insulated pipe， which has guiding significance for optimization of the production process of thermal insulation tube， reduction of cost and increase of efficiency.