To effectively protect the Forbidden City’s Tai-he Palace, its dynamic characteristics and seismic responses to frequently occurring earthquakes were studied by finite element analysis methods. Based on hypotheses that tenon-mortise joints and bracket sets were simulated by spring elements, and that column roots were of swivel restriction, a finite element model of Tai-he Palace was built. By modal analysis, the basic frequency and main modes of the palace were obtained; from time-history analysis, displacement and acceleration response curves of typical nodes, and internal force response curves of typical elements were obtained. Analysis shows that basic frequency of Tai-he Palace is 0.9 Hz and that its main modes are of translation. During frequently occurring earthquakes, the structure vibrates steadily, although its peak displacement as well as internal force response values are within permitted limits. From this, it can be concluded that tenon-mortise joints and bracket sets are helpful for seismic mitigation of damage to the structure.