The invention belongs to the technical field of fault finding tools of power lines and discloses a 485 line fault finder. The 485 line fault finder includes a finder and a wire hooking wire. An operation lamp, a transmission lamp, a receiving lamp and a 645 receiving lamp are arranged on the finder. The rear face of the finder is provided with a charge jack while the front face of the finder is provided with two detection leads connected through 485 adaptors. The wire hooking wire is provided with a conical wire hooking groove. Two sides of the conical wire hooking groove are provided with a metal sheet and an arc-shaped sheet respectively. The other end of the arc-shaped sheet is provided with a spring in elastic connection. The metal sheet is provided with an indication lamp connected through a lead. The wire hooking clamp is provided with an insulation rod. The detection lead penetrates through the insulation rod so as to connect with the metal sheet in the wire hooking clamp. According to the invention, an alligator wire clip is changed to the wire hooking clamp, and a handheld insulation rod can be hooked on a to-be-detected wire directly, so that technical problems of high risks and detection inconvenience in the prior art are solved effectively.