Epoxy resin (EP) nanocomposite materials with excellent tribological properties are highly desired for many engineering applications requiring low friction and wear. Adding carbon nanofiller is regarded as one of the most potential solutions to solve the serious dry wear problem of epoxy matrix. Herein, we report a new filler of carbon nanocages (CNC) prepared by the method of MgO templates to improve its dry friction performance through filling epoxy into the internal hollow space of CNC. Relative to neat epoxy, the friction coefficient (0.249) and wear rate (7.98 x 10(-7) mm(3) Nm(-1)) are reduced by 55.6% and 51.9% for the optimized CNC/EP nanocomposites, respectively. Even compared to typical graphene/epoxy nanocomposites, the wear rate is also reduced by up to 21.8%, as well as greatly enhancing the mechanical properties, thereby effectively protecting epoxy matrix and improving its dry friction. Such great tribological performance is attributed to unique structure of CNC, enabling the multi-functional collaboration of physical confinement, self-lubrication and wear-debris collection for CNC fillers, and making it the most potential carbon-based nanofiller for EP-based nanocomposite material system. More than that, it also provides insights for designing other advanced carbon-based nanofillers.