Cerium oxide/silicon rubber was prepared via mechanical blending. Mechanical and frictional properties, as well as thermal stability after thermo-oxidative ageing were investigated in this rubber composite. 3D surface profilometry, scanning electron microscopy (SEM) and thermogravimetry analysis (TGA) were used to study the friction surface characteristics, friction mechanism and thermal stability, respectively. Additionally, swelling experiments were carried out to investigate the variation of crosslinking density. After thermo-oxidative ageing, the tear strength of cerium oxide/silicon rubber decreases. However, in the early ageing stage, improvements in tensile strength, elongation at break, and frictional performance are caused by crosslinking density increments. Moreover, the addition of cerium oxide remarkably im-proves the re-crosslinking degree during ageing process, which in t decreases the number of holes on the friction surface and endows the silicon rubber with better mechanical and frictional properties, as well as thermo-oxidative ageing resistance.