Abstract: For column-beam splice joint with flange-column of fabricated steel structure， the mechanical behavior and connection are very complex， and there are many influencing factors for its strength and rigidity． ANSYS finite element analysis software was used to analyze and simulate the beam-column's joint of the steel framed structure with or without braces． The seism-resisting behavior of the fabricated steel frame beam-column joints including the hysteretic behavior，ultimate bearing capacity，ductility coefficient，failure mode etc． were studied． The results show that for the fabricated steel frame beam-column joints with supports the joint's rigidity and bearing capacity are increased greatly． To bolt connection of beam-column joints with braces，the bearing capacity is improved by more than three times，and to welded joint，it is improved by about 50 percent，ductility factor is increased by about 70 percent． Through setting braces，the plastic hinge is transferred effectively，and the failure locations are located on the truss beam outside of the brace，which has played an important role in protecting the connection，and accorded with the design requirement ofstrong connection，weak component． Meanwhile hysteresis curves display more fully under the cyclic reverse loading，indicating better aseismic performance．