The invention provides a novel nano-carbon-
fiber heating floor and a preparation method thereof. The preparation method comprises the following steps: (1) placing nano 
polyacrylonitrile fibers prepared by electrostatic 
spinning in a 
roasting oven, performing heat treatment by using air as a medium, and performing 
carbonization treatment under 
nitrogen environment so as to obtain carbonized nano 
polyacrylonitrile fibers; (2) stirring 
plant protoplasm fibers and a cationic surface 
active agent under a closed condition and normal temperature till a uniform mixture is obtained, adding the carbonized nano 
polyacrylonitrile fibers and nano 
graphite powder in the mixture, stirring the carbonized nano polyacrylonitrile fibers, the nano 
graphite powder and the mixture at a high speed, and preparing sheet type flexible 
macromolecule materials by a hot-pressing technology; (3) fixing 
metal-sheet electrodes at both ends of the sheet type flexible 
macromolecule materials by a silver solution so as to form a conductive heating layer; and (4) shearing a 
solid-wood layer, an 
insulation layer, the conductive heating layer, a 
temperature control layer, another 
solid-wood layer and a surface treatment layer with appropriate sizes from bottom to top, and performing combination so as to form the nano-carbon-
fiber heating floor.