Abstract: The concentration of volatile organic compounds (VOCs) was detected by collecting soil,soil gas and groundwater samples from the chemical plant’s remaining sites to characterize the characteristics of VOCs pollution and elucidate its migration mechanism.The results showed that the site was polluted by various VOCs,and the concentrations of trichloroethylene and cis-1,2-dichloroethylene were the highest and the distribution area was the widest.The concentration of trichloroethylene decreased with the increase of soil depth,and the exceedance rates were 12.90% (soil),25.00% (phreatic layer),19.15% (confined water) and 77.41% (soil gas),respectively,but the concentration increased with the increase of soil depth and reached the highest concentration at 5m depth (1 610mg·kg^-1).After reaching the phreatic layer,it migrates laterally under the action of dispersion,convection and diffusion,and vertically migrates into the confined water layer where the permeability of the water-barrier layer of the phreatic floor is large,and then transverse migrates to expand the polluted area again.Under volatilization,trichloroethylene in vadose zone and aquifer become zone pollution sources and surface pollution sources respectively,resulting in a large range of soil gas pollution,and the soil gas pollution area affected by surface pollution sources increases with the increase of soil depth.This study can provide useful reference for the analysis,definition and remediation of chemical site pollution.