Abstract: In the traditional live-line operation lead replacement process, there are problems such as difficult control of lead swing and hard guarantee of safety distance. This research is based on portable lead fixing device technology. Through a dual-point clamping mechanism and modular design, it has achieved precise control of the spatial position of the leads. The device is composed of an insulating support rod, a support assembly and a lead wire fixing part. It is connected to the crossarm by a quick clamping mechanism. The lead wire clamp can be adjusted in position according to the length of the lead wire. The application effect evaluation shows that the device has controlled the lead swing range within ±5°, improved the spatial control accuracy by 67%, reduced the total operation time from 85 min to 35 min, and increased the overall efficiency by 59%. The insulation strength of the device has reached 35 kV/mm, and the safety risk level has been reduced from Grade III to Grade I, providing a safe and reliable technical solution for live-line operations in the power system.