Abstract: Displacements along the transmission line were measured through the 3-D DICM (Digital image correlation method). Statistics and spectra of the wind-induced displacements were analyzed, and the results illustrated that under the wind loads, horizontal vibration of the transmission line is dominated by the first symmetric out-of-plane mode coupled with certain participation of in-plane mode, and as the wind speed increases, the contribution of in-plane mode become significant; as to the vertical vibration of the transmission line, the dominated modes include the first symmetric out-of-plane mode, the first and second symmetric in-plane modes. Overall, three modes mentioned above can be chosen to analyze the wind-induced vibration of the transmission line, which are sufficient to reflect the main components of wind-induced vibration energy; with the increasing of wind speed, the PDFs of the wind-induced displacements are non-Gaussian any more, and peak factors should be adjusted accordingly.