With the rapid development of urbanization in our country and the industrial restructuring under the policy of "retreating from two to three", a large number of industrial enterprises in cities need to be shut down or relocated, and industrial land will be re-planned for commercial or residential use. Because such sites have been used for industrial purposes and the soil in the site has been polluted to varying degrees, due to the relatively short period of industrialization in China, the pollutants in most industrial sites have not been massively dispersed with groundwater and are mainly sourced Pollution exists, that is, the main need to repair the soil within the site. Most of these former industrial land are located in the urban area, and the potential for appreciation of the land after the land is developed into commercial or residential land in the later period is large. As a result, the spontaneous motive force for the remediation of contaminated sites is strong and the repair costs are relatively adequate. However, the acceptable remediation period is as short as possible. Most owners require completion in half a year or one year. In addition, the average owner requires "complete" removal of contaminants from the remediation effect, ie the removal of contaminants in the soil takes precedence over the contaminant control in the soil. Taking a dye factory in Beijing as an example, in 1964 moved to Chaoyang District, located in the East Third Ring within the excellent geographical location. Completely discontinued in 2003, 40 years of industrial history led to the soil by a variety of dyes, organic pigments, and heavy metals pollution. A total of 50,000 square contaminated soils need to be rehabilitated. Due to the development of the plots, the construction period is only 6 months. The owners demanded to "thoroughly" remove the pollutants, including reducing the content of heavy metals in the soil. In foreign countries, similar cases can be repaired for several years or even decades. According to the characteristics of the project of remediation of contaminated sites in our country - "short construction period, exhaustion, budget enough", the author thinks that the strategy of "ectopic repair technique, supplemented by in situ repair technique" should be adopted in soil remediation technology, which should be prioritized The introduction and absorption of repair techniques include: curing stabilization, thermal desorption / thermal analysis, incineration / co-processing, steam extraction, biological ventilation and degradation. Relatively speaking, the repair project using in situ technology has a greater risk. As shown in the figure below, the project completion rate using mainstream in-situ repair technology is only 41%, while the completion rate using mainstream ectopic repair technology is as high as 80%. Uncertainties in site stratigraphy and geologic structure have led to greater uncertainty in the effects of in situ repair techniques and the need for longer repair cycles, or even for various reasons, failed to reach the repair targets.