In this study, zeolite ZSM-5 was synthesized by using the powder of pistachio shell ash. This powder was used as the source of both silica and aluminum. In this thesis feasibility of three plant fibers including date palm, coconut shell and pistachio shell has been investigated. The powder of pistachio shell was prepared in two step burning, first step in furnace with liquid fuel for 6 hours and then in the electrical furnace at 800 ?C for 24 hours. The powder of Coconut shell and date palm were prepared by burning in electrical furnace at 1000 ?C for 26 hours nnd at 800 ?C for 10 hours respectively. To determine the composition of powders, they were analyzed using XRF analysis. XRF results showed that composition of pistachio and coconut shell ashes are almost the same. Pistachio shell ash SiO2/Al2O3 mol ratio was 3.1 and coconut shell ash was 2.25. To remove impurities and undesired component, the powder from pistachio shell ash was treated by different amount of 1M HCl. In this thesis 3 sample were prepared. The final powders were again under XRF analysis. Comparison of the XRF results of initial powder (p-1) and powders after treatment with HCl (p-2, p-3 and p-4) showed that acid treatment could eliminate most of undesired oxides in powder. Results indicate that 60% of impurities in p-2 sample, 94.2% in p-3 sample and 99.5% in p-4 have been eliminated. Silica and Aluminum amount of initial powder was increased after acid leaching from 6.5 to 17.2 and from 2.1 to 7.0 respectively for p-2 sample and from 6.5 to 23.3 and 2.1 to 13.0 respectively for p-3 sample. These powders have been used as raw material for zeolite synthesis. In order to synthesize ZSM-5 zeolite, sodium silicate solution was added to adjust the SiO2/Al2O3 mole ratio in p-1 and p-2 powders. In this study ZSM-5 zeolite with SiO2/Al2O3 mole ratio of 80 and 170 were synthesized. XRD pattern were used for structural identification and relative crystallinity for all samples. Morphology and Crystalline size of samples were examined under Scanning Electron Microscopy (SEM). Zeolite with SiO2/Al2O3 mole ratio of 80 has been chosen for adsorption tests because of lower amorphous phase. XRD patterns and SEM images of zeolites indicate that p-3 powder because of lower impurities is the best sample for zeolite synthesis. Two samples synthesized from p-2 and p-3 powder and standard sample that synthesized in our laboratory were subjected to adsorption tests using benzene and toluene gas in fixed bed column. Concentration of benzene and toluene before and after column is measured by GC analysis. The adsorption capability of synthesized zeolite from pistachio shell ashes was tested and compared with standard one. It was observed that there was no significant difference in adsorption performanc