Ni/H Zeolites catalysts were prepared by impregnation, starting from HY-Zeolite, H beta-Zeolite and H-mordenite with nickel precursor salts, NiCl2, NiSO4 and NiCO3. The total number, NTSA, and the acid strength were found dependent on the nickel precursor salt. High catalytic activity, selectivity and stability of the modified zeolites in isobutene dimerization was attributed to the acidic properties of nickel modified zeolites. HY-Zeolite modified with NiCO3 resulted more active and selective to dimerization reaction. The prepared catalysts were characterized by EDSX, SEM, and Adsorption/Desorption of N-2 at 77 K, NH3 chemisorption and Ammonia Temperature-Programmed-Desorption (NH3-TPD) and FT-IR of adsorbed pyridine. NH3-TPD and isobutene adsorption revealed an acid sites a new distribution and apparition of acid sites not present in the protonated zeolites. Catalytic activity and reactor behavior were studied in a continuous downstream fixed bed reactor at 298 K, 27.6 kPa (4 psig), and WHSV = 0.27 h(-1).