Nanocrystalline LaFeO3 was prepared by a simple molten-salt method with La2O3 and FeCl3·6H2O as main starting materials. The nanocrystal1ine samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) for the phases and morphology. Their gas-sensing properties to triethylamine, C2H5OH, gasoline, C6H6 and CH3COCH3 were investigated. The results demonstrated that pure LaFeO3 nanocrystal1ine with uniform grain sizes and an average diameter of about 40 nm was formed when calcined at 800 ℃. Moreover, the gas sensor made of the nanocrystalline LaFeO3 sample showed high sensitivity as well as good selectivity to dilute triethylamine. The LaFeO3 sensor showed the sensitivity as high as 7.9 to even 25 μg/g triethylamine at 250 ℃, and the response and recovery time are 6 and 13 s, respectively.