Taking Chengde-Pingancheng 500 kV double-circuit line project and Ningdong-Shandong ±660kV DC power transmission line project as examples, in this paper, the 45° wind load on tension towers is calculated and the wind loads in different angles are compared. The internal force increase of tower legs and the influence on tower weight under 45° wind conditions are also analyzed, based on the comparison with 90° wind conditions. It was suggested that 45° wind should be considered as unnecessary condition for the design of tension tower of EHV transmission lines.