A root canal file for oral disease therapy is provided with various tapers and a deep screw groove, the longitudinal profile shape of the cutting edge includes rectangle and cone; the cutting edge is folded as helix conic along the axial direction of the file. The root canal file adopts novel medical Ni Ti shape memory alloy materials, which can be freely bent with the structure of complex root canal system, no real deformation exits in the treatment process, the utility model is provided with convenient operation of pull and rotation, good cutting effect and high efficiency, the scraps are easy to be exhausted for the deep screw groove, the root canal file isn't fracture after reused for many times, and the cutting edge is uneasy to wear. The surface is uneasy to rust when disinfection treatment, so the service life is long.