Abstract: In this paper, the synthesis of methanol in CO₂ hydrogenation on NiO supported In₂O₃(110) defect surface was studied with the aid of density functional theory (DFT) calculation. Two pathways for methanol synthesis including HCOO route and reverse water gas (RWGS) route were analyzed. The reaction energy and activation energy barrier of each elementary reaction in these two routes were calculated. The results show that the existence of NiO support can enhance the adsorption of CO₂ on In₂O₃ catalyst and promote the generation of methanol via the HCOO route. In HCOO route, the hydrogenation of HCOO to H₂COO is the rate-determining step, and it requires to overcome the activation energy barrier of 1.66 eV. The NiO-supported In₂O₃(110) defect surface exhibits a promoting effect on the hydrogenation of CO₂ to methanol via HCOO route, which, hence, improving the efficiency of methanol formation.