In high-strength-steel composite eccentrically braced frames (HSS-EBFs), links and braces are made of Q345 steel, whereas other structural members are made of Q460 steel. This structure can reduce member section sizes and thus the weight of the steel and achieve improved economic efficiency by reducing the amount of steel used and applying HSS. To compare the seismic performance of K-type HSS-EBFs (K-HSS-EBFs) with traditional K-type EBFs (K-EBFs), in this study, we designed four K-HSS-EBFs and four K-EBFs of different structural heights. We used nonlinear static pushover analysis and nonlinear dynamic analyses to investigate the seismic performance of the K-HSS-EBF and K-EBF models. The results indicate that both K-EBFs and K-HSS-EBFs well satisfy seismic requirements and that the deformation of the K-HSS-EBFs was more obvious than that of the K-EBFs. However, the comparatively smaller member section sizes of the K-HSS-EBFs can reduce the steel weight and project building costs.