Abstract: A super-high-rise office building comprises three levels of basement and 57 stories above ground，whose main roof has a height of 296 m． The structural system is the one of steel-concrete frame-core tube with strengthened stories． Programs such as ETABS and PMSAP were used to do elastic analysis and the check on the comfort of the floors under frequent earthquake． The results showed that the period ratio，inter-story drift angle and comfort requirement of the floors could meet the limits of the code． The FEA results of the typical joints of outrigger trusses also showed that the stress in joint zone was smaller than the designed strength of the steel，and without stress concentration． Moreover，program Perform 3D was used to analyze the structure response under rarely occurred earthquake． The result showed that the core tube，frame column，outrigger truss，overall behavior，deformation and energy dissipation of members could all meet the requirements of the code．