Abstract: n-Butanol is an important raw material and ideal biomass fuel. Conversion of ethanol into n-butanol in different atmospheres was studied using hydroxyapatite (HAP)-supported Ni as a catalyst (Ni/HAP). Ni/HAP was prepared by a sol-gel method and characterized by XRD, BET, ICP-AES, TEM and SEM-EDX. The effects of reaction atmosphere (N₂ and H₂), Ni loading and reaction conditions on ethanol conversion and n-butanol selectivity were investigated. The results show that the reaction atmosphere has a significant impact on the reaction. Using 12%Ni/HAP as a catalyst in H₂ atmosphere under 300℃ with H₂ GHSV of 3000 h^-1 and ethanol LHSV of 2.0 h^-1, ethanol conversion rate of 15.6% and n-butanol selectivity of 83.6% are obtained, and the catalyst performance has no noticeable decline within 128 h. Ethanol conversion, n-butanol selectivity and catalyst stability increase by 2 times, 4.2 times, and 3 times than those in N₂ atmosphere, respectively.