Firstly, the dynamic characteristics of the high-end valve hall and valve group of UHV Xinsong converter station are tested and analyzed on the spot. The dynamic response of the valve hall structure under different seismic excitations with a peak value of 0.4 g is calculated. The acceleration, displacement and stress responses of the key parts of the valve hall are obtained, and the seismic performance of the valve hall under strong earthquake is analyzed. The results of dynamic characteristics test and modal analysis are consistent. The first three frequencies of the high-end valve hall are between 2.0 and 5.0 Hz. The vibration modes are X and Y translations and X-Y plane torsion. The main vibration frequency of the valve hall structure is close to the predominant earthquake frequency, and it is easy to resonate under earthquake. Seismic response analysis of the valve hall under strong earthquake shows that the dynamic amplification factor of acceleration at the top of the steel column and the installation position of the through-wall sleeve are larger; and the structural response has a certain torsional effect. However, the maximum component stress of the valve hall structure is far from the yield stress of the material, and the overall seismic performance of the steel structure valve hall is better.