To improve the construction and installation efficiency of wind turbine towers and overcome the residual stress issues of traditional welded joints, it innovatively introduced the concept of detachable design into concrete-filled steel tube (CFST) wind turbine tower joints. Static tests and numerical simulation analyses were performed on four prefabricated concrete-filled circular steel tube (CFCST)-gusset K-joints with arc-shaped end plates and a prefabricated circular hollow section (CHS)-gusset K-joint with arc-shaped end plate. The test results show that all the CFCST-gusset K-joints exhibit two distinct failure modes: web member and gusset plate failures, while the arc-shaped end plates and single bolts are always in good condition. The bearing capacity of the joints is significantly correlated with the failure mode. Based on the verification of the correctness of the finite element model, a parameter expansion analysis of this type of joint had been performed. The results show that the gusset plate-to-web thickness ratio μ and the arc-shaped end plate-to-gusset plate thickness ratio β have significant influence on the failure mode and bearing capacity of the joints. It is suggested that μ ≥ 2 and β ≥ 1.5.