With the increasing level of power line voltage

the high voltage power line is developing very fast. When this power line is active

there is electric field around with them which would cause electro-magnetic interference. The higher the voltage level of the power line is

the worse of the electro-magnetic interference effect is. For the safety of the human being and the equipments

we must pay attention to the electric field caused by the higher voltage level of the power line

especially for the ultra high voltage of the power line. We must analyze the distributing electric field of power line iron tower when ADSS cable spanning with the high voltage power line.