The invention discloses a controllable nanometer graphene cutting method, and relates to graphene. An amorphous carbon nanorod deposits at the tip end of a tungsten tip to be recrystallized through afocused electron beam, or nanometer carbon onions or graphite flakes are directly attached to the tip end of the tungsten tip, and a nanometer knife is prepared; constant bias voltages are exerted onthe tungsten tip and electrodes at the two ends of a golden wire, the nanometer knife is precisely moved according to the nanometer dimension step length, and the arbitrary precise cutting is conducted on the edge of graphene step by step. Through the cutting technology, any wanted shapes and sizes can be obtained, and the cut edges are smooth. By taking electron diffraction pictures of graphene,all chiral directions can be obtained and the edges of corresponding chiral structures are cut. Fewer layers of graphene of any shapes and patterns can be cut out instead of only obtaining angle-fixededge shapes like metal particle etching. Controllable cutting is conducted on the crystal structure and chirality of the cut edges, the cut edges are quite precise and smooth, and the roughness degree is 1-2 nm or lower.