The invention provides a safe method for entering tangent tower equal potentials for live-wire operation in 660kV direct current lines. First, an operator, wearing complete shielding clothing, climbs a tower from the ground to the position where a tower body and a conducting wire are at the same level. During the climbing process, the operator keeps a distance of 4.5-7.0 meters from an electrified body; second, the operator arrives at a high electric field from the towel body by an insulating carrier and the sum of the distance between a grounding body and the operator and the distance between the operator and the electrified body is kept between 4.6 meters and 7.0 meters; and the operator, when arriving at the electrified body, keeps a distance of 4.5-7.0 meters from the grounding body. The safe method can provide high safety for operators during the process of entering the tangent tower equal potentials in the 660kV direct current transmission lines for live-wire operation which therefore can be safely and conveniently conducted so as to improve the safe and stable operation level of the transmission lines.