Abstract: The load case category and numerical calculation procedure of tension leg platform (TLP) in-place global performance analysis are systematically stated. Meanwhile, the frequency domain method and time domain method are simply introduced. According to a TLP front end engineering design project at South China Sea, modeling principles related to panel meshing, calculation methods of TLP mass properties, stiffness introduced by tendons and risers, and TLP external damping are introduced. At last, the main results of in-place global performance analysis are listed. The procedure and methods used could be a reference for other analogous projects at South China Sea.