The invention belongs to the field of mine materials, and particularly relates to an interface adhesive used for reinforcement of fragmentized coal bodies and a preparation method of the interface adhesive. According to the technical scheme, coal-based carbon nanofibers are prepared by using an electrostatic spinning method, the coal-based carbon nanofibers are subjected to amination, then under the action of a catalyst, the aminated coal-based carbon nanofibers react with diphenyl-methane-diisocyanate and mannose in sequence, and the adhesive is prepared. The interface adhesive mainly aims tosolve the technical problem that the interface bonding effect of existing cement grout and coal is poor, the preparation method of the adhesive is simple, the adhesive is convenient to use, the molecular structure is lipophilic and has certain hydrophilcity, the dispersibility of the adhesive in the cement grout is good, the wettability and the permeability of the cement grout on the surfaces ofthe coal bodies are obviously improved, and the interface bonding ability of the cement grout and the coal is greatly improved, so that the fragmentized coal bodies and the cement grout are cemented to form a whole compact body.