The 500 kV double circuit transmission line can only be operated by helicopter sling method due to the dense conductor arrangement, which makes it very difficult for the operator to choose the path to access equipotential. A feasible helicopter sling method to access the path region of equipotential is proposed by taking the double triangle and hexagonal wire arrangements of two typical same-tower double-circuit transmission lines as the objective and considering the spatial position relationship between helicopter and wire. The field decomposition method is used to decompose the three-dimensional boundless field into bounded sub-regions, and the field strength of the helicopter body at different locations during approaching is calculated by ANSYS software to obtain the safe distance between the helicopter and the wire. After specifying the combined margin of equal potential for operator, the optimal path for the operator to access the equal potential is proposed in combination with the calculation of the human body surface field strength. The practical application of helicopter sling method in live line operation of 500 kV Gufeng line A and B shows that the operators can enter the equal potential operation safely from the area 0~15 ° above the horizontal plane of the conductor while the helicopter is 8 m away from the conductor.