The nitrogen compounds in Liaohe atmospheric residue (LHAR) have been analyzed through Fourier transform infrared spectroscopy (FTIR), gas chromatography coupled with mass spectrometry (GC-MS), etc. to investigate the mechanism of reaction during slurry-phase hydrocracking. Their chemical structures have been exploited, and the experiment data revealed that the molecular weight of nitrogen compounds after hydrocracking was increased in comparison to that in crude oil in the same fraction. Basic nitrogen compounds in Liaohe light vacuum gas oil (VGO) were composed of quinolines, etc., and non-basic nitrogen compounds consisted of carbazoles, amines, etc. The contents of basic nitrogen compounds were decreased with the increase of the boiling point, but non-basic nitrogen compounds changed oppositely. Meanwhile, nitrogen compounds could be hydrocracked, and the products were transferred into some "lighter" fractions, such as diesel and VGO.