With the rapid development of modern society， energy demand and environmental problems are gradually aggravating， ground source heat pump systems can be used to extract shallow ground temperature-a clean energy source to achieve the goals of energy conservation， emission reduction and full utilization of resources. An important factor affecting the efficiency of geothermal energy extraction in ground source heat pump technology is the development and application of backfill materials. This article reviews the thermal conductivity， mechanical properties and construction performance of backfill materials in ground source heat pump technology， as well as their current problems and development trends. It points out that the current research and development of thermal conductivity of backfill materials can achieve higher thermal conduction efficiency， but it often affects the mechanical strength and other physical properties of the materials， and increases its construction difficulty. Phase change materials may be the key to solving the performance defects of backfill materials； in addition， with the development of science and technology， the combination of numerical simulation and experimentation can greatly improve theoretical innovation and engineering benefits.