Abstract: In this article， the object of study is a kind of key joint in modular prefabricated high-rise steel structure． Both the finite element analysis and experimental research on the static behaviors were carried out，the limit bearing capacity and the flexural rigidity were studied． The result show that this kind of joint has relatively large rotational stiffness and relatively high limit bearing capacity． The failure mainly caused by the instability of the web member of the truss beam in test，which resulted in the out-of-plane buckling of the whole truss-beam; there is no slip on the high strength bolt connection of the joints．