The invention relates to the technical field of optical fiber communication. The invention discloses an optical fiber fault point auxiliary positioning and online optical fiber auxiliary fiber aligning device. The device comprises an operation table, a first positioning fixing piece, a second positioning fixing piece, a movable fixing piece and an operation part, the first positioning fixing piece, the second positioning fixing piece and the movable fixing piece are all arranged on the operation table. The movable fixing piece is movably arranged between the first positioning fixing piece andthe second positioning fixing piece; the optical fiber can wind around the first positioning fixing piece, the movable fixing piece and the second positioning fixing piece, and the position of the movable fixing piece on the operation table can be changed under the telescopic action of the operation part so that the curvature radius of the optical fiber connected among the three fixing pieces canbe changed. According to the invention, the macro-bending degree of the optical fiber reference point is changed on line, so that the optical path attenuation change of the optical fiber occurs at thereference point position, the specific fiber core and position where attenuation occurs are quickly determined through the test comparison of the optical time domain reflectometer, the purpose of searching the fiber and a fault point is achieved, and the maintenance benefit and quality of an optical cable line are improved.