Abstract: Gallium atoms have been introduced into the framework of Y zeolite by treating zeolites with an aqueous solution of ammonium hexafluoro gallate. At ambient conditions and space velocity of 7.2h-1, desulfurization of various model fuel containing about 500×10-6 sulfur was studied over the modified Y zeolite (\Ga\AlY). The adsorption capacit of the adsorbent for the sulfur from tetrahydrothiophene (THT), 4,6dimethyldibenzothiophene (4,6DMDBT), 4methyldibenzothiophene (4MDBT), and dibenzothiophene (DBT) are 17.4×10-3, 14.5×10-3, 5.8×10-3 and 16.9×10-3 respectively. The charge on S atom of THT, 4,6DMD BT，4MDBT, and DBT, calculated by density functional theory (DFT) method, are -0.298, -0.214, -0.188 and -0.211 respectively. Implying that the electron density on S atom decrease in the order THT﹥4,6DMDBT≈DBT﹥4MDBT which agrees with the order of the sulfur adsorption capacity. Only one third Al atoms could be substituted by Ga due to the different position of Al atoms in the NH4Y. The adsorption capacity of adsorbent for the sulfur from thiophene is 7.7×10-3. The regenerated \Ga\AlY recovered 85% original capacity and the adsorption capacity of adsorben is 6.5×10-3.