In order to investigate the influence of three main performance parameters of isolator, i.e. equivalent horizontal stiffness Kf, pre-yield stiffness K1 and yield force Qd, on the bilateral seismic response of base-isolated structures with different site condition, eighteen base-isolated structures different between Kf、K1 or Qd were designed. Based on SAP2000, the bilateral seismic responses of each isolated structure excited by four seismic waves of different site types are analyzed respectively. It is found that, the acceleration response and the base shear response of base isolated buildings under bilateral seismic excitation are influenced remarkably by the aforementioned isolator parameters, and the effect of the parameters on the isolation layer’s displacement response varies from different site conditions. Under the condition of Ⅰ、Ⅱ、Ⅲ site classified in Chinese seismic code, both the top floor’s maximum acceleration and the maximum base shear of base isolated structure show an obvious increase trend with the increasing of Kf,K1 and Qd, However, the isolation layer’s maximum deformation does not change evidently. Under the condition of Ⅳ sites, the effect of isolator parameters on the isolation layer’s maximum deformation is significant and represents obvious regularity. As Kf,K1 and Qd increases, the peak deformation value of isolation layer decreases sharply with the biggest decline of above 80%.