The design wind load of transmission line is essentially equivalent static wind load based on the combination of mean static wind load and fluctuating wind dynamic effect. Five main transmission line design specifications in China and abroad, such as GB 50545—2010, DL/T 5551—2018, IEC 60826—2017, ASCE NO. 74—2020 and BS EN 50341—2012, are selected to give the calculation expression of the conductors and earth wires wind load. Based on the structural random vibration theory and the basic principle of wind engineering, a typical theoretical model of wind of transmission line load is derived. The differences in the values of basic calculation parameters such as computed altitude, basic wind velocity, shape coefficient, altitude variation coefficient of wind pressure and gust response coefficient are deeply compared. Taking typical 110 ~ 330 kV, 500 ~ 750 kV and 800 kV and above transmission lines as examples, the influence of the revision of DL/T 5551—2018 load code on the wind load of transmission lines is analyzed in detail, and the root cause of the difference between the design value of load and the international standard is revealed. The research results can provide reference for further optimization of relevant calculation parameters in the new specification, so as to effectively improve the safety, reliability and economy of wind-resistant design of transmission line structures.