This paper presents a 3D full-wave finite element method (FEM) combined with short-open calibration (SOC) and short-open-load (SOL) technique. In order to accurately acquire the intrinsic propagation characteristics of various guided-wave structures, our proposed SOC/SOL technique is successfully incorporated into 3D full-wave FEM algorithm/solver. Hence, the port discontinuities between the core guided-wave structure and the feeding network can be effectively removed out. Thus, the intrinsic unite-length parameters including their propagation constants and characteristic/wave impedances can be finally achieved. A few numerical examples are given out to demonstrate the efficiency and accuracy of our proposed full-wave approach.