In order to evaluate the anti-disaster capability of power transmission tower under strong earthquake, the direct dynamic method was used to analyze the load bearing capacity under earthquake for a typical power transmission tower of 500 kV double-circuit lines by taking real earthquake record as the seismic input. The results show that the load impact on tower with the basic fortification intensity under earthquake is generally smaller than that of non-seismic actions, which means tower has good anti-seismic capability. However, the seismic impact of rare strong earthquake exceeds the load bearing and deformation capacity of typical towers. So, it is suggested that the power transmission towers, such as those for large-crossings, which demand highly for anti-disaster capability, should impose higher anti-seismic requirements and consider anti-seismic design under strong earthquake. Meanwhile, the impact of vertical earthquake should be considered in the seismic checking calculation of tower with long cross-arm cantilever.