The invention discloses an external breaking prevention alarm lamp mounting device which comprises a first plate piece and a mounting bracket; the first plate piece is used for being fixedly connectedwith an alarm lamp; the middle section of the first plate piece is provided with a wire clamping mechanism; the wire clamping mechanism comprises a supporting mechanism used for supporting and a wiretouching action and a clamping plate used for lamping; when the supporting mechanism is oppressed by an external force, a clamping arm is automatically closed for clamping; the mounting bracket is provided with a notch for clamping the plate piece; the top of the mounting bracket is provided with a CCD for real-time operation video return transfer; the external breaking prevention alarm lamp mounting device further comprises an aircraft; the mounting bracket is installed on the aircraft; the aircraft is also provided with a controller and a communicator; the CCD is electrically connected withthe controller and the communicator; and the aircraft enables the supporting mechanism to touch a power transmission wire, so that the clamping arm clamps the power transmission wire. For the external breaking prevention alarm lamp mounting device, casualties cannot be caused by a potential difference formed between an unmanned aerial vehicle and the power transmission wire; and line power failure is not needed during concrete construction, and mounting can be completed, so that timeliness of mounting is guaranteed.