Abstract NO2 and H2S are highly toxic and corrosive gases that severely pollute the environment and damage the health of human beings. Developing sensitive sensor for efficiently detecting NO2 and H2S molecules is highly demanded. In this work, density functional theory calculations are performed to investigate the adsorption characteristics of NO2 and H2S on the graphene surface decorated with group 10 transition metals (Ni, Pd and Pt). NO2 and H2S molecules are physically adsorbed on pristine graphene due to weak interactions. Decorating graphene with metals can significantly enlarge the interactions between gas molecules and graphene, in which the adsorption energy and charge transfer are 7–10 times and 3–10 folds higher than those on pristine graphene, respectively, demonstrating the strong chemisorption on the metal-decorated graphene. Especially, Ni and Pt decorated graphene are highly sensitive to the NO2, while for H2S molecule detection, Pt-decorated graphene is more preferable. Besides, we demonstrate that graphene with group 10 metal decoration can capture the NO2 gas more effectively than H2S because H2S molecule fails to dope graphene by Fermi level shifts (Δ(Ef-ED) = 0 eV). The as-obtained insights could provide useful guidance on the design of graphene-based sensor for advanced performances.