Under the influence of long-term complex operating environment, the mechanical properties of transmission towers are easily affected by corrosion, resulting in a decrease in buckling load and endangering the structural stability of the tower, which is not conducive to the safe and economic operation of the power grid. In this paper, a finite element model of 110 kV cup-type transmission tower considering corrosion is established, and the variation law of buckling load of high voltage transmission tower with corrosion position and corrosion degree is studied. The results show that when the corrosion rate of the main leg of the tower leg and the main leg of the tower body reaches 50%, the critical load of the tower will be reduced by 23.7% and 56.5% respectively compared with that without corrosion. When the corrosion position is located in the main leg of the tower or the tower mast, it will increase the possibility of buckling of the tower.