Thermo-gravimetric analyzer (TGA) was used to determine the thermal behavior of stainless steelmaking dust and FTIR was used to detect the components of off-gas. The TGA results indicate that three mass loss/gain stages exist in the thermal process. The mass loss of the dust in the first stage results from the evaporation of moisture and the reaction between dissociated carbon and metal oxides in the dust. The evaporation of moisture within the dust happens at 90-350 ℃ and the formation of carbon dioxide happens at 250-470 ℃. The mass gain of the dust in the second stage results from the oxidation of metals in the dust by the oxygen at 470-950 ℃. The third stage is a slow mass loss process, and some metals in the dust are evaporated into the atmosphere in this stage. The evaporation of metals is carried out mainly at 900-1 200 ℃ and the dust is sintered at high temperature over 1 200 ℃.