Abstract: The transformation of nitrogen-containing compounds of Liaohe Atmospheric Residue (LHAR) during slurry-bed hydrocracking was investigated using Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS). It was turned out that the major basic nitrogen containing compounds were quinoline in light VGO (350~400 ℃), while some part of pyridine and acridine existed as well. C_1~5 carbazole and indole were dominating non-basic nitrogen containing compounds. For heavy VGO (400~450 ℃), the major nitrogen containing compounds were acridine and pyridine. After hydrogenation, the major basic nitrogen containing compounds of the light VGO became C_1~7 quinoline, benzoquinoline, and C_1~2 acridine, while the major non-basic nitrogen compounds were C₂, C₃ and C₇ indole. For the heavy VGO, the major nitrogen containing compounds had become acridine and carbazole. The content of quinoline before and after the hydrogenation reaction in the atmospheric residue fraction decreased with the elevation of boiling point. In addition, after hydrogenation the concentration of quinoline in LHAR had become higher. During the slurry bed hydrocracking reaction, the nitrogen-containing heterocyclic compounds were reduced and part of the non-basic nitrogen containing compounds was converted to basic nitrogen containing compounds.