Abstract: The effects of different model nitrogen containing compounds on the catalytic cracking of o-xylene were investigated in a fixed bed. The adding amount of N element was 4000μg/g and the active component of the catalyst was USY zeolite. The results indicated that the conversion of o-xylene is reduced by adding pyridine or quinoline. On one hand, the increase in coke yield after adding acridine is related with its adsorption on catalysts. On the other hand, acridine induces o-xylene to produce more coke and hydrogen, promoting the hydrogenation and opening reactions of aromatic rings. Compared with the blank test, the conversion of o-xylene is improved slightly by adding acridine, and both the yield of dry gas and the yield of LPG increase greatly.