Strong earthquakes can cause damage to underground structures. The Yingliangbao hydropower station, which experienced significant tremors during the 2022 Ms 6.8 Luding earthquake, is located just 10 km from the epicenter. To assess the impact of the earthquake on the stability of the surrounding rock, a combination of field investigation and numerical simulation was conducted. The field investigation revealed displacements ranging from 0 to 6.55 mm in certain areas of the rock, with localized collapses. The numerical simulation showed that the response of the underground cavern rock is closely linked to the acceleration and the frequency of the seismic waves. Displacements and stresses in the rock varied significantly at different seismic wave acceleration. However, there were discrepancies between the numerical calculations and the field monitoring data due to factors such as the neglect of local geological weak surfaces. Despite these differences, the numerical simulation accurately represented the overall response of the site to the earthquake, with the magnitude of the disparities in displacement data being on the millimeter scale. The earthquake also may cause a 2.3 % increase in the size of the plastic zone in the surrounding rock. Additionally, the residual displacement and maximum stress fluctuations in the sidewall of the underground chamber decreased with increasing frequency within a specific range, while the volume of the plastic zone initially decreased and then increased with higher frequencies of the seismic waves.