Abstract: An investigation was carried out on a fixed-fluidized bed reactor system to study the distributions and forms of sulfur deposited on adsorbent for removing SOx and NOx in flue gas through catalytic cracking, and the catalytic cracking performance of the adsorbent was studied as well. Results show that during catalytic cracking reactions, more than 80% of the sulfur deposited on the adsorbent could be desorbed and distributed into liquid product, cracking gas, pre-fluidized water and atomizing/stripping water with mass fractions of 2.6%, 41.5%, 27.2% and 2.8%, respectively. The sulfur in liquid product is mainly existed as alkyl thiophene, thiophene, mercaptan and thioether; the sulfur in cracking gas is existed as H2S; the sulfur in condensed water is mainly existed as SO42-, SO32-, S, S2O32- and S2-. However, it seems that the presence of adsorbent do not have significant effect on the catalytic cracking of hydrocarbons.