The effects of carrier gases, including nitrogen, air, and carbon dioxide, on diesel-contaminated soil were studied under the low temperature thermal treatment (LTTT). The removal rate of total petroleum hydrocarbons (TPHs), the contents of soil carbon, nitrogen, volatile organic contaminants (VOCs) and semi-volatile organic contaminants (SVOCs) were quantitatively investigated after LTTT at 250℃. The results showed that the removal rates of TPHs exceeded 98% under all three carrier gases, meeting the relevant national standards of soil quality. Carbon content remained relatively stable, primarily due to the impact of a coke film formed on soil surface during LTTT. The contents of ammonium nitrogen and nitrate nitrogen in the soil increased significantly after LTTT under nitrogen gas flow, but decreased under the gas flow of air and carbon dioxide. VOCs in diesel-contaminated soil were mostly removed under all three carrier gas conditions after LTTT, except that a small amount of benzene left under the carbon dioxide gas flow condition. However, small amounts of low-molecular weight PAHs, such as naphthalene and phenanthrene, were generated. In summary, LTTT is an efficient and feasible method to remediate diesel-contaminated soil.