IEC TR 62681:2014 provides general guidance on the electromagnetic environment issues of HVDC transmission lines. It concerns the major parameters adopted to describe the electromagnetic environment of a High-Voltage Direct Current (HVDC) transmission line, including electric fields, ion current, magnetic fields radio interference, and audible noise generated as a consequence of such effects. Engineers in different countries can refer to this Technical Report to ensure the safe operation of HVDC transmission lines, limit the influence on the environment within acceptable ranges, and optimize engineering costs.