Kinetic measurements were carried out for the catalytic cooxidation of mixed 1-butanethiol, 1-octanethiol and 2-methyl-2-propanethiol in gas-liquid system. A mechanism which can explain the enhancement of the oxidation of 2-methyl-2-propanethiol by normal thiols and agree well with the experimental results was set up, and the Michaelis-Menten type kinetic equation was derived accordingly. Researches also demonstrate that the interactions between different thiol molecules during the catalytic cooxidation of mixed thiols in the sweetening process are the general role.