For the labor-intensive, low work efficiency, greater risk and other issues of human traces for 500kV transmission line inspection, a new walking device for 500kV transmission line four bundled conductors was proposed. This walking device adopted battery as a power source, was suitable for large span transmission lines, which can automatically span spacers, linear hanging string and shockproof hammer. Described the design and function of walking devices in detail, and finally introduced the field trial. The test results showed that the walking device could achieve wire walking requirements and design standards.