Variable masses of nano cerium oxide(CeO__2) were added into nano silica(SiO__2) to prepare the well-dispersed SiO_2-CeO_2suspension(SiO_2-CeO_2), cetyltrimethyl ammonium bromide(CTAB) was used to adjust the compatibility of SiO_2-CeO_2 with rubber matrix, then SiO_2-CeO_2 modified by CTAB and curing formulas were mixed with fresh natural rubber(NR) latex to prepare NR/SiO_2-CeO_2 nanocomposites that contained 0–10 parts of CeO_2 by a new emulsion compounding method. The morphologies, cure characteristics, mechanical properties and thermal-oxidative stability of NR/SiO_2-CeO_2 nanocomposites were investigated. The results revealed that the presence of CeO_2 in NR/SiO_2-CeO_2 nanocomposites was favorable for enhancing the interaction between NR matrix and fillers, helped to get smaller SiO_2-CeO_2 particles with narrower particle size distribution, further improved the crosslink densities and mechanical properties of NR/SiO_2-CeO_2 nanocomposites vulcanizates. Meanwhile, the addition of CeO_2 increased the active energy at least 4.66%, obviously improved the thermal-oxidative aging-inhibiting properties of NR/SiO_2-CeO_2 nanocomposites. Additionally, nanocomposites containing CeO_2 promoted T g shift to high temperature direction, causing the nanocomposites featured higher tanδ at 0 oC and lower tanδ at 60 oC and exhibited comparable wet grip and lower rolling resistance when NR/SiO_2-CeO_2 nanocomposites were used in tire tread compound. Variable masses of nano cerium oxide (CeO_2) were prepared into nano silica (SiO__2) to prepare the well-dispersed SiO_2-CeO_2suspension (SiO_2-CeO_2), cetyltrimethyl ammonium bromide (CTAB) was used to adjust the compatibility of SiO_2-CeO_2 with rubber matrix, then SiO_2-CeO_2 modified by CTAB and curing formulas were mixed with fresh natural rubber (NR) latex to prepare NR / SiO_2-CeO_2 nanocomposites that contained 0-10 parts of CeO_2 by a new emulsion compounding method. The morphologies, cure characteristics , mechanical properties and thermal-oxidative stability of NR / SiO_2-CeO_2 nanocomposites were investigated. The results revealed that the presence of CeO_2 in NR / SiO_2-CeO_2 nanocomposites was favorable for enhancing interaction between NR matrix and fillers, helped to get smaller SiO_2 -CeO_2 particles with narrower particle size distribution, further improved the crosslink densities and mechanical properties of NR / SiO_2-CeO_2 nanocomposites vulcanizates. Meanwhile, the addition of CeO 2 increased the active energy at least 4.66%, obviously improved the thermal-oxidative aging-inhibiting properties of NR / SiO 2-CeO 2 nanocomposites. Additionally, nanocomposites containing CeO 2 promoted T g shift to high temperature direction, causing the nanocomposites featured higher tan δ at 0 oC and lower tan δ at 60 oC and exhibited comparable wet grip and lower rolling resistance when NR / SiO_2-CeO_2 nanocomposites were used in tire tread compound.