Abstract: ZSM-5 zeolite synthesized from amine-free system was dealuminated by acid treatment under different conditions. Four ZSM-5 zeolites with different aluminum content and pore structure were prepared. The samples were characterized by XRD, XRF, BET, and NH3-TPD techniques to analyze the crystallinity, element composition, morphology and size, pore structure as well as acidity distribution. The performance of 1-hexene oligomerization was evaluated over ZSM-5 zeolites at the conditions of 4.5 Pa，245 ℃ and mass hourly space velocity of 0.5 h-1. The results show that with increasing the Si/Al ratio，the conversion of 1-hexene decreases while the yield of dimers shows a tendency of firstly increase and then decrease. The maximum yield is obtained at the Si/Al ratio of 102. The ZSM-5 zeolite with lower Si /Al ratio has more by-products and more carbon deposition. From yield of dimers and raw material utility consideration, the ZSM-5 zeolite with Si/Al of 102 is the most suitable catalyst for the production of jet fuel component.