Joints are the key factors that determine the construction difficulty and structural safety of prefabricated steel structures. However, the existing prefabricated joints of square steel tube and H-shaped steel beam frame have few reference forms, and there are still a series of problems in practical engineering applications, such as construction difficulties and poor applicability. Therefore, a new type of column-column-beam joint with variable beam height and its construction scheme are designed in this paper. The joint is bolted rather than welded in the process of field prefabricated. It can solve the problem of vertical and horizontal connection of steel frame structure through one joint at the same time, thus effectively saving construction cost and ensuring construction quality. In addition, the detailed modeling and comprehensive mechanical properties analysis of the joint scheme are carried out in this paper. The ultimate bearing capacity, stiffness characteristics, failure modes and hysteretic behavior of joint schemes under low cyclic loading are also evaluated.