Abstract: Coking occurs easily in the process of residue hydrogenation.The coke might cause a series of harms such as equipment blocking,catalyst deactivation,product yield reduction and so on.To prevent coking,the basic characteristics of the coke is necessary to be revealed,which might provide reference for the design of hydrogenation process,the design of kerosene co-refining process,catalyst design and industrial production.The hydro-cracking conditions of residue in industrial units were simulated by batch-type autoclave and the coke was obtained.The coke in residue hydro-conversion process was analyzed and characterized by using infrared spectroscopy( IR),nuclear magnetic resonance( NMR),thermogravimetric analysis( TG),X-ray diffraction( XRD),scanning electron microscopy-energy dispersive spectrometry( SEM-EDS) and elemental analysis.The results show that the atmospheric residue coked during hydrocracking when the reaction temperature is 450 ℃ and the hydrogen consumption ratio is 2.19%,the gas yield is 8.90%,the coke yield reaches 6.95% and the H/C atomic ratio of the coke is 0.66. Besides,severely dehydrogenated reaction is happened during the coking process. The condensation degree of aromatic nucleus of the residue is 0.699 4 and the aramid-carbon ratio is 0.395 6,the condensation degree of aromatic nucleus of the coke is 0.400 5 and the aramid-carbon ratio is 0.769 5.The coke contains a large amount of aromatic ring structures,and the weight loss of coke is most severe at the temperature of 187 ℃ and 584 ℃.The main component of coke is C and also contains several kinds of elements such as O,Na,Cl,Ca and V.The coke is globular or irregular block in shape,and the size is 30 to 50 nm.Some of the coke accumulates and becomes porous and the size is 500 to 1 000 nm.