Abstract: Transmission tower is a key part of power transmission, which is urgent to carry out health monitoring research. Two-dimensional dynamic displacement is an important index in health monitoring, however, the existing monitoring methods are limited in measuring the displacement response of the transmission tower. To this end, this paper proposes a two-dimensional dynamic displacement reconstruction method based on measured strain response. Firstly, the transmission tower is simplified as cantilever beam with a variable cross-section, then the strain decoupling formula is proposed to decompose the two-dimensional reconstruction problem into one-dimensional reconstruction problem, and a two-dimensional strain-displacement mapping method combined with the stochastic subspace identification theory, which realize the transformation from strain to displacement. Subsequently, the wind-induced vibration simulation of the transmission tower is carried out, which suggest that the reconstruction error of the highest point is only 1%, and the proposed method still has good robustness in the high noise case. To further verify the feasibility of the proposed method, a full-scale test of the transmission tower was carried out, and the results demonstrate that the maximum difference between the reconstructed displacement value of the highest point and the total station observation value is 5.4 mm, accounting for only 6% of the measured value.