To quantitatively assess the damage of base-isolated structures caused by aftershocks， the seismic performance of base-isolated structure under main shock-aftershock sequences is evaluated by damage index. The velocity response spectrum reflects the maximum energy of the structures produced by the external force. A main shock-aftershock sequence construction method based on the matching of force and energy is proposed， and the artificial main shock-aftershock sequence constructed by this method is used as an excitation. Moreover， the elastoplastic time-history analysis of the base-isolated structure is carried out， and the earthquake damage index is used to evaluate the seismic performance of the structure. The results show that the artificial main shock-aftershock sequence construction method based on force and energy matching can effectively simulate the real main shock-aftershock sequence ground motion. Comparing the damage index of base-isolated frame model under each working condition， the peak acceleration of aftershocks increases， the damage index of the superstructure increases by over 20%， and the damage index of the lower isolation layer increases by over 15%. The aftershock makes the damage index increases obviously， and the structure is severely damaged.