Abstract: This paper presents a research on floor-by-floor assembled steel beam-through braced frames. By introducing a numerical simulation method of the moment-rotation constitutive model of joints, the influence of the joint rigidity and strength on the seismic performance of the structure system is studied. The analysis results indicate that the impact of the joint rigidity on the structure's frequency of vibration is small. Structures with different joint rigidities have different failure modes under the static pushover. The hysteretic behavior of the structure is closely related with the rigidity of joints. When the rigidity of joints is smaller than four times of the line rigidity of columns, the structure's maximum story drift ratio cannot satisfy the limit under severe earthquakes required by the present Chinese codes. Meanwhile, the strength of the joints slightly affects the structure ultimate strength under the static pushover and has little influence on the hysteretic behavior and story drift distribution of the structure under severe earthquakes.