The invention relates to the technical field of a deicing device and particularly relates to a power transmission line deicing mechanism. The power transmission line deicing mechanism includes a casing, a sliding clamping device for driving the casing to slide along an overhead ground line, a swing arm connected with the casing for swinging and hitting an ice-covered line, and an incomplete gear device for driving the swing arm to swing up and down, wherein the incomplete gear device includes a driven gear connected with the swing arm, a transmission gear for driving the driven gear to rotateintermittently and a first driving member for driving the transmission gear to rotate, and the transmission gear includes a gearless section and a meshing section meshing with the driven gear and hasthe function of automatically removing ice from the ice-covered line.