In this study, an active Ni–Co/Al₂O₃ catalyst for steam reforming of ethanol (SRE) was reported. Results indicated that the dispersion of active species can be tuned by preparation methods, i.e., by step—step impregnation method and co-impregnation method separately. By comparing the activities and stabilities in the temperature range of 250–650 °C under atmospheric pressure, and correlating the characterization results of H₂ chemisorption, XRD, HRTEM and TGA, we found the catalytic performance were dependent on the surface species dispersion over support which could be modulated by preparation process. The ethanol conversion on Ni–Co/Al₂O₃, Co/Ni/Al₂O₃ and Ni/Co/Al₂O₃ catalysts were 68.7%, 50.9%, 36.6% at 350 °C, corresponding to the metal species dispersion data 31.5%, 29.1% and 28.0%, respectively. TEM results confirmed these differences corresponded to the metal particles size of the bimetallic catalysts distribution. Higher dispersed catalyst exhibited higher anti-coking properties and stabilities. Under the optimized conditions, the ethanol conversion, H₂ and CO₂ selectivities were 97.2%, 88.9% and 87.4%, respectively during a 100 h reaction over Ni–Co/Al₂O₃ catalyst at 550 °C, LHSV of 7.5 h⁻¹ and a C₂H₅OH/H₂O molar ratio of 13.