Nowadays, the soil contamination from heavy metals, e.g. Hg, has become one of the most important environmental issues. In order to remove Hg from the soil and fulfill the requirements of industrial or agriculture use, numerous measures were proposed. Thermal desorption among them is paid much attention due to some unique advantages. The paper described the system layout and general working principle of thermal desorption. In addition, the key points when adopting this method for Hg-contaminated soil remediation, were summarized according to the existing scientific studies and engineering cases. Finally, the direction for future development of the technique was also pointed out.