The mechanism of alkali fusion reaction of alkyl sulfonates has been investigated by a gas chromatographic technique. An alkali metal hydroxide such as LiOH, NaOH, KOH, RbOH, and CsOH was mixed with an alkyl sulfonate and the reaction temperature was varied from 250° to 500°C. The reaction products were isolated and identified as 1-olefin and internal olefins by gas chromatography and IR-spectroscopy. Neither the reaction temperature nor the kind of alkali metal hydroxide had any influence upon the kind of reaction products. However, when the alkali fusion reaction was carried out under a continuous nitrogen stream in a pyrolyzer connected with a gas chromatograph in series, the relative retention value of the pyrolyzates with respect to n-nonane, an internal standard, varied with the reaction temperature and the kind of alkali metal hydroxide used.