Abstract: The thermo-stability of 2-fluorobutane is studied through gas chromatography. 2-fluorobutane was synthesized by nucleophilic substitution reaction of AgF with 2-bromo-butene and then thermo-decomposed in the injector of GC under different temperatures. The thermo-elimination products of 2-fluorobutane were analysed on a capillary column of SE-54 (44 m× 0.22 mm× 0.25 μm ). The results indicated that 2-fluorobutane start to decompose at a temperature above the room temperature and decomposes quickly at temperatures above 120 ℃. The main products proved to be iso-butene, trans-butene and cis-butene. Based on the results of quantitative and qualitative analysis, the mechanisms of the thermo-elimination reaction of the 2-fluorobutane are discussed, mechanisms of formation of the products are explained by the transient state theory of tetratomic rings and the rearrangement of carbon cations.