Due to the hard carbon nanofibers and abundant welded joints among the nanofibers, the hard carbon aerogels display robust and stable mechanical performances, including super-elasticity, high strength, extremely fast recovery speed (860 mm s-1) and low energy loss coefficient (<0.16). After tested under 50 % strain for 104 cycles, the carbon aerogel shows only 2 % plastic deformation, and retained 93 % original stress.