Abstract:TMVOC software was used to simulate the migration behaviour of contaminants under “natural” environmental conditions and attenuation process of contaminants during the in-situ air sparging process in a simulated vadose zone which was contaminated by BTEX. The best air injection rate as well as the quantity and distribution of the required aeration wells were determined, and further simulation was performed for remediation results. In the unsaturated zone BTEX mainly migrated vertically by gravity and migrated horizontally by capillary; in the saturated zone, however, the groundwater flow direction became the leading migratory direction of BTEX which dissolved into groundwater at the same time and whose pollution plume could reach the bottom of the vadose zone. It only required 180 days to completely remedy the BTEX contaminants under the condition that the air was injected into the aquifer at the rate of 12 cubic meters per hour through seven aeration holes located at the bottom of the vadose zone. Under these conditions, the effective remediation radius of a single aeration well is about 5 meters; the effective remediation scope is better than that of injecting the air into the vadose zone from the central or the lower part of the aquifer.