The invention discloses an auxiliary tool for preventing a worker from falling from a power transmission strain tower insulator string, and the tool comprises two positioning discs which can sleeve aninsulator, and two handle bodies. The long sides of the positioning discs at one side are provided with two symmetric T-shaped grooves, and the interior of each T-shaped groove is provided with a plurality of positioning blocks, wherein positioning grooves are respectively formed between the adjacent positioning blocks. Each handle body comprises a handle rod and a handle pedestal, and the handlepedestal is also provided with a positioning pin in a long axis direction. Two handle pedestals of the handle bodies are respectively connected to the T-shaped grooves of the two positioning discs atthe same position in a rotating position, thereby enabling the two positioning discs and the two handle bodies to be connected with each other. The invention has the following beneficial effects that(1), the tool can balance the force of the insulator in a horizontal direction; (2), the tool improves the safety of the worker; (3), the tool improves the work efficiency of the worker.