Abstract Peroxymonosulfate (PMS) was utilized as an oxidant for methyl mercaptan odor (CH 3 SH (G) , ∼80 ppm/v) removal in wet scrubbing process, and the proposed reaction mechanism was investigated in detail. Under alkaline condition (pH ∼ 12) with PMS, the removal of CH 3 SH (G) maintained high levels of >95%. The reaction was so quick that no methyl mercaptan ion (CH 3 S − ) in aqueous solution was detected before the depletion of PMS. PMS not only reacted with CH 3 S − , which was dissociated from the dissolved CH 3 SH (aq) in alkaline solution, but also directly oxidized the dissolved CH 3 SH (aq) . It was found that 3 mol of PMS would be necessary to oxidize 1 mol of CH 3 SH. The major product of the oxidation of CH 3 SH was methanesulfonic acid (CH 3 SO 3 − ). Additionally, the stability of PMS, by adding sodium silicate (Na 2 SiO 3 ), was very well maintained even under strong alkaline conditions (less than 5% decomposition). In conclusion, PMS was extremely suitable for CH 3 SH (G) removal in wet scrubbing process with the existence of Na 2 SiO 3 , especially under alkaline condition (pH ∼ 12).