Abstract: To clarify the failure mechanism and mechanical property of coupled concrete-filled steel tubular (CFST) splice joints, static load experiment was conducted on 6 scale models of coupled CFST splice joints. Then, software ABAQUS was used for non-linear finite element analysis. By changing the radius-thickness ratio of tower column, thickness of gusset plats and the presence of stiffening plates, the failure mode of joints and the equivalent stress of gusset plates were analyzed. The results indicate that the failure zones of joints without stiffening plates located on gusset plates. Failures of stiffening plates were caused by instability of compression bars. Load of joints with stiffening plates was larger than that without stiffening plates. Joints with stiffening plates present weak sensitivity towards thickness of gusset plates, initial eccentricity and radius-thickness ratio of tower column. High-stress zones of gusset plates without stiffening plates mainly concentrate at its middle and lower sections and the lower section of web members. High-stress zones of gusset plates with stiffening plates mainly concentrate at its middle and lower sections. If there is no buckling failures of web members, when the tower column radius-thickness ratio is no more than 27.4 (27.4), the thickness of gusset plates is the same. The bearing capacity of joints decreases with the increase of tower column radius-thickness ratio. When the tower column radius-thickness ratio is greater than 27.4 (27.4), the decrease magnitude of bearing capacity slows with increase in the thickness of gusset plates. When the thickness ratio of gusset plates and tower column walls is no more than 2 (2), the bearing capacity of joints will increase with . When 2, the increase magnitude of bearing capacity decrease with increase of the thickness of tower column walls.