A radial-circle-lined grid shell, its height changed step by step in the radial direction, is adopted in the roof steel structure of the Citizen Water Sports Center in Jiangyin, China. And the Spatial Crossing Tubular (SCT) joint is used for the connection of pipe members. Because the force transmission in the roof structure is different from the traditional truss structure, a lot of SCT joints are in a complicated loading state. The joint forces include axial forces and in/out-of-plane moments. To investigate the mechanical behavior and the load-bearing capacity of a typical SCT joint in such complicated loading condition, a full size model test of the typical SCT joint is conducted. The test process is summarized in the paper, together with the finite element calculation of the typical SCT joint in test conditions. By comparing the numerical results with the test results, several significant parameters of the connection are investigated, including the stiffness change of the joint, the transmission mechanism of forces, the ultimate load-bearing capacity and the failure mode of the joint. After investigation, several useful suggestions are proposed for the SCT joint design. They are also valuable for the design of similar SCT joints under complicated loading condition.