The effect of Sr addition to LaNiO3 perovskite catalysts was studied for the steam-CO2 reforming of methane. Xray diffraction (XRD) patterns indicate that different ionic radii caused distortion of the perovskite lattice and produced alien phases such as La2-xSrxNiO3 +/-delta and Sr0.5La1.5NiO4. Moreover, these different phases affected reduction behavior. The influence of Sr mainly appeared in the steam-CO2 reforming of methane reaction. SrO species adsorbed CO2 during the reaction and produced SrCO3, which has a better ability of eliminating carbon sources by producing La2O2CO3, and by this means, carbon formation was significantly suppressed. However, the addition of Sr species covered the support sites leading to large-sized nickel particles by reducing the interaction between the support and active metals, thus the catalytic activity was decreased by an increase in Sr concentration on the catalysts. Therefore, we recommend using a small amount of Sr in the perovskite-based catalysts to obtain superior resistance to carbon deposition with moderate catalytic activity.