The composite cross-arm structure is quite different from the conventional tower, which has a great impact on the safe distance of live working, the entering equipotential method, and the electric field protection requirements of workers. This paper analyzes the influence of ± 500kV composite crossarm on the safety of live working through experiments and simulation calculations. The minimum approach distance and the minimum combined gap distance of live working on the ± 500kV composite cross-arm line are 3.5m and 3.9m, which are 0.1m larger than the conventional tower requirements. On composite crossarm line, we can enter the equipotential along the composite crossarm. When entering and exiting equipotential along the composite crossarm, the maximum electric field strength on the worker’s body appears at the head and shoulder. The results of this paper can assure the safety of live working on ± 500kV composite crossarm lines.