Abstract: By PMM8053B electromagnetic radiation analyzer and EHP-50C electromagnetic field probe with power frequency, electric field intensity of 500 kV super high-voltage transmission line was measured in some area and electric field intensity in open zone of the area was calculated by use of equivalent charge method. Through comparing the measured and calculated results by use of Matlab, conclusions were gotten that the calculated results are mainly consistent with the measured ones and electric field intensity in buildings and woods is far less than the one in open zone.