In this work, a steady-state magnetic coupled with transient thermal 3D finite element model (FEM) was developed for simulating a continuous induction welding of carbon fiber 5HS fabric/poly-ether-ketone-ketone (PEKK) thermoplastic composites. The multiphysics problem was solved by the electromagnetic field equation and the heat transfer equation. The temperature distribution on the interface of composites was researched by FEM. The induction welding was conducted on the CF/PEKK composites with different coil speed. The temperature on the interface was measured to compare with FEM results. The mechanical properties of induction welded specimens were evaluated by interlaminar shear strength tests, single-lap joint static tensile lap shear tests and single-lap joint fatigue tensile lap shear tests.