The invention provides a lead wire connecting method for a live working robot. On the basis of a main mechanical arm, an auxiliary mechanical arm and a camera collecting image data of a work scene ona robot platform, the mechanical arms are controlled by a control chamber to complete the following works: the auxiliary mechanical arm clamps a lead wire; the main mechanical arm takes out a wire clamp from a toolbox; the main mechanical arm hangs the wire clamp on the lead wire through a wire groove on one end of the wire clamp; the auxiliary mechanical arm threads the lead wire through a wire groove on the other end of the wire clamp; a pneumatic wrench at the end of the main mechanical arm aligns a nut on the wire clamp and screws the nut; and the main mechanical arm and the auxiliary mechanical arm release clamping jaws and withdraw. According to the method, the lead wire can be bridged on the lead wire through the mechanical arms of the live working robot under the condition of continuous power supply, and so negative influence caused by the power outage is avoided and the reliability of power supply is improved.