Abstract: As a novel structural system, the high-strength steel composite Y-eccentrically braced frame (Y-HSS-EBF) combines the advantages of the high strength of high-strength steel and the large energy dissipation capacity of the eccentrically braced frame. To investigate the seismic performance of Y-HSS-EBF structures, a series of substructure hybrid tests were conducted with a three-story three-span Y-HSS-EBF as the prototype. The bottom-story steel frame with Y-eccentric brace of the prototype was taken as the experimental substructure, and the rest of the prototype was taken as the numerical substructure in OpenSees to establish the substructure hybrid test model. According to the hybrid test results, the validity of the hybrid test model was verified, and the main seismic performance indexes of the hybrid test model were analyzed. The results show that during different earthquakes, the test results of the hybrid test model were in good agreement with the numerical simulation results of the global structure. During a seldom earthquake, the plastic deformation of the experimental substructure mainly occurred at the web of the link, whereas the beam-columns and braces of the experimental substructure remained in the elastic domain, which conformed to the concept of multi-aspect seismic fortification.