In this paper, we selected the Wanshan mercury mine soil as the research object, processed and studied by thermal analysis of low temperature plasma, By study of temperature, time, additives and other process parameters on mercury removal rate and treatment after Mercury, we analysed and compared the process on the mercury containing waste residue , exploring its mechanism of action and summarizing the key factors influencing the process exhaust system. The main results were as follows: (1) The main form of mercury in contaminated soil was organic binding state (52.5%). Secondly, the oxide bound state was (32.5%), acid extractable state was (8.13%) and residual state was (6.25%). (2) Under the condition of 500 ℃ and 40 minute, the residual mercury concentration was only 1.44 mg·kg-1. (3) Under the condition of 400 ℃, with the extension of time, the removal rate of total mercury in soil increased gradually, and the pyrolysis process was basically completed within 40 minute. In the 200~1 600 mg·kg-1 interval, the higher the initial oncentration of mercury, the smaller the removal rate of total mercury in soil. (4) The synergistic effect of calcium chloride on the pyrolysis of mercury containing soil was the best, followed by citric acid and sublimation sulfur, and sodium sulfide had a certain inhibitory effect. (5) The pulse voltage was 21.1 kV, and the discharge frequency was 650 Hz, which was the best parameter to match the high voltage pulse power supply with the low temperature plasma reactor. The total mercury removal rate could reach above 89.73%.