The Yungang Grottoes are one of most famous ancient Chinese Buddhist temple grottoes in the province of Shanxi. To preserve the grottoes against the earthquake which is one of the most important factors leading to damage of the grottoes, a 3-D finite element dynamic model of the 19th grotto's west ear-grotto is built to explore its dynamic responses under earthquakes. The simulation results show the cliff has a tendency to dump, and the distribution of final state displacement on thin rock mass between grottoes is rhythmical. Larger acceleration plays a decisive role in the displacement responses. The maximal peak ground acceleration (PGA) amplification factor could reach ∼ 130. The rock mass ranging from the roof of ear-grotto to the top rock mass absorbs most of the energy and is the most dangerous region where collapse often happens.