Abstract: The sulfides in MTBE and their formation mechanisms during MTBE production were analyzed. It is found that all sulfur compounds in MTBE are from the refined LPG, one of stocks for synthesis of MTBE. The sulfides include thiols, thioether and disulfides. Thiols and disulfides are directly from refined LPG，while thioethers are attributed to the thioetherfication reaction of thiols with isobutene by catalysis of strong acidic cation exchanged resin. It is recognized that the analysis of sulfur compounds in MTBE can be helpful to estimate the operation problems and to further reduce sulfur content in LPG and MTBE during deep desulfurization processes.