A　novel　methodology　of　carbon-diffusion-dominated　continuous　cooling　treatment　(CC)　during　the　bainite　transformation　is　proposed　and　implemented　on　a　high-carbon　nanobainitic　steel.　Nanobainite　(NB)　microstructure　composed　of　bainitic　ferrite　lath　with　a　thickness　of　approximate　to　36　nm　is　obtained　by　successive　heat　treatment　processes,　including　cooling　the　sample　from　240　to　216　degrees　C　at　a　rate　of　0.1　degrees　C　min(-1),　then　cooling　down　to　120　degrees　C　at　a　rate　of　0.2　degrees　C　min(-1)　followed　by　austempering　at　120　degrees　C　for　12　h.　Several　technological　routines　involving　oil　quenching　+　tempering,　single-stage　austempering　+　tempering,　and　two-stage　austempering　+　tempering　are　compared.　The　effects　of　heat　treatment　processes　on　the　microstructure　and　mechanical　properties　are　unveiled.　Importantly,　after　the　CC　process,　the　tensile　strength　is　2049　MPa,　the　yield　strength　is　1552　MPa,　the　elongation　is　2.5%,　the　impact　toughness　is　11.5　J,　and　the　hardness　is　60.7　HRC.　Notably,　the　comprehensive　mechanical　properties　of　CC-processed　samples　are　superior　to　that　of　other　heat-treated　samples.　Microstructure　analyses　reveal　that　the　CC　process　significantly　refines　the　bainitic　ferrite　lath　thickness　while　increasing　the　volume　fraction　of　NB.　Thereby,　effectively　shrink　blocky　retained　austenite,　and　finally　enhancing　the　overall　mechanical　properties.