The 2-methylthiobenzothiazoleis (MTBT) synthesized from the substrate of 2-mercaptobenzothiazole (MBT) and the methyl source of tetramethylammonium chloride (TMAC) by electrolysis method under the normal temperature and pressure condition. The solution with volume of 100 mL, c(MBT)=0.1mol/L and n(TMAC):n(MBT)=3:1 was electrolyzed under the condition of the quantity of electricity is 1.5 times of theoretical value (964.85 C), the yield of MTBT is higher than 88%. The DFT study believe that the species coming from electro-reduction of TMAC accelerate the electro-oxidation of MBT and formation of MTBT, this is in accord with experimental results.