Abstract: The reduction products of 5-fluro-2-nitrophenetol were separated on a 30 m×0.25 mm ZB-5Ms capillary column. The helium gas flow rate was at 0.8 mL/min(consist flow), and oven temperature was held initially at 120 ℃ for three minutes, then elevated by 20 ℃/min to 260 ℃ and held for ten minutes. The injector temperature was 270 ℃. Few sample was introduced in GC by split injector .Five compounds were identified by GC/MS and the main by-product was validated by¹H-NMR as 4-fluor-2-chloro-6-ethoxyaniline, which had not been reported before.