Autothermal reforming of methane was studied over La-doped ceria-zirconia-supported Rh catalysts. The CH4 conversion increased from 49 to 60% on increasing the content of La3+ from 5 to 15%, while further increase in the La3+ content led to a slight decrease on both CH4 conversion and H-2 selectivity. H-2-TPR and UV-vis DRS spectrum showed that the interaction between Rh and the support was enhanced by increasing the content of La. We speculated that a so-called "Rh-La interfacial species" was formed on the surface of the support, which played an important role in catalytic activity. The balance between exposed Rh and the "Rh-La interfacial species" was necessary to improve the catalytic activity. Upon increasing the Rh loading on 15% La-doped ceria-zirconia support, the balance was built, i.e., CH4 conversion increased from similar to 60 to 69% by increasing Rh loading from 0.1 to 0.5 wt% and only 2% conversion was elevated by doubling the Rh loading from 0.5 to 1.0 wt%.