The brick-vault hall of Longchang Temple at Baohua Mountain is a representative of a series of Ming Dynasty brick-vault halls—a unique architectural heritage type in China. In order to evaluate the structural safety of this architectural heritage in earthquakes, we set up a three-dimensional finite element model to analyze its dynamic properties, seismic response spectrum and seismic time history in order to obtain the natural frequencies, modal modes, seismic effect, and seismic deformation and stress response. The results show that the structure of the hall features high symmetry and high torsional rigidity. The degrees of influence of earthquake on the vibration of the hall are as follows:roof, side walls and arch on the second floor, eaves of the first floor, side walls and arch on the first floor. Under the Intensity 7 frequently-occurring earthquake, precautionary earthquake, and rarely-occurring earthquake, the most dangerous position of the hall is the junction of the arched window impost and sill wall on the side far away from the stairs on the first floor. In addition, prone to the tensile damage, each arch impost is a weak position in an earthquake. Finally, a seismic strengthening strategy for the brick-vault hall of Longchang Temple is presented based on the results of dynamic properties and seismic behavior analysis.