Abstract: The fastness of transmission tower is very important to transmission line operation safety. The simulation test for tower foot corrosion under special environment is performed; and the corrosion mechanism is investigated by using electrochemical measurement. Results show that the corrosion is caused by the dust cover which exposed to environment rich in water and oxygen. The protection measure is proposed based on the corrosion mechanism and applied in transmission line tower. The re-test shows the proposed protection measure has anticipated effect.