Strong　metal-support　interaction　(SMSI)　is　a　crucial　strategy　for　modulating　the　activity.　Finely　tailoring　the　size　of　the　support　to　the　nanoscale　still　faces　significant　challenges.　Herein,　for　the　first　time,　C60　carbon　cluster　is　utilized　as　a　nano-support　to　anchor　ultrafine　Ru　nanoclusters　to　create　a　Ru-C60　cluster-cluster　co-catalyst.　The　unique　geometric　structure　of　the　nano-support　C60　enables　the　construction　of　a　strong　cluster-cluster　interaction　(SCCI),　quite　different　from　traditional　SMSI.　La-modified　Ru-C60　presents　a　surprising　discovery　that　NH3　can　even　be　synthesized　at　150　degrees　C,　and　exhibits　an　unprecedentedly　high　NH3　synthesis　rate　at　400　degrees　C.　C60　not　only　acts　as　an　electron　buffer　to　balance　the　charge　density　of　Ru　sites,　but　also　stabilizes　more　metallic　Ru　active　sites　with　a　smaller　size　due　to　its　spatial　and　SCCI　effect,　thereby　achieving　superior　catalytic　performance　over　a　wide　range　of　temperatures　and　pressures.