Abstract: In order to study the effect of multidimensional seismic action on the structural susceptibility of double-deck frame piers, a nonlinear finite element model is constructed with the help of OpenSees based on the low-week reciprocation test of double-deck frame piers, and the hysteresis curves and skeleton curves obtained from the simulation and the experiments are compared to validate the reasonableness and validity of the finite element model established. Based on the principle of spectral compatibility, 20 suitable ground vibration records are screened, and the peak ground acceleration and the spectral acceleration of the basic period of the structure are selected as the indexes of vector ground vibration intensity. Vector IM-based susceptibility surfaces are used to study the susceptibility of double-deck frame piers under one-, two- and three-dimensional seismic actions in different damage states. The results of the study show that: compared with the scalar IM, the susceptibility failure probability calculated by the scalar IM is a definite value, while the susceptibility failure probability calculated by the vector IM is a numerical interval. When the damage probability of double-decked framed piers is 50% in the severe damage state, the values of SA under one-dimensional earthquakes are from 1.13 g to 2.0 g, and the values of PGA are from 0.93 g to 1.5 g; the value of SA under 2D earthquake is 0.25 g~2.0 g, the value of PGA is 0.33 g~1.5 g, the value of SA under 3D earthquake is 0.27 g~2.0 g, and the value of PGA is 0.28 g~1.5 g; seismic susceptibility analysis of double-deck frame piers based on vector IM can significantly reduce the dispersion of the prediction of the structure's damage level, and improve the prediction of aseismic performance accuracy, and thus more accurately assess the aseismic capacity of the structure; the probability of susceptibility failure of 3D earthquakes is slightly higher than that of 2D earthquakes, while the probability of susceptibility failure of 2D earthquakes is significantly higher than that of 1D earthquakes.