Abstract: In order to study the influences and reaction chemistry of basic nitrogen compounds in FCC process，the model compounds of quinoline and 7，8-benzoquinoline were used to investigate the conversion rules of N-containing compounds and nitrogen distribution in FCC products by fixed fluidized bed（FFB）.The reaction chemistry of samples were studied by molecular simulation.The results showed that the addition of basic nitrogen compounds reduces the conversion and influences the product distribution.Quinoline and benzoquinoline are most susceptible to alkylation.In the process of hydrogen transfer，the nitrogen ring in the quinoline molecule is more easily saturated，and then the ring-opening cracking reaction generates aniline nitrides； while for 7，8-benzoquinoline，the benzene ring in the middle of the molecule is most probably to be saturated first by hydrogen transfer reaction，and then be converted to aliphatic amine or ammonia，but not generate aniline.Aniline and five element nitrogen heterocyclic compounds are generated by cyclic condensation reaction of ammonia with olefins.The macromolecular nitrogen compounds are produced from small nitrogen-containing molecules by alkylation or cyclization-condensation reactions.

Key words: catalytic cracking, basic nitrogen compound, quinoline, 7,8-benzoquinoline, conversion rule