Abstract: We review the frequency domain dynamic analysis method of mooring system, and apply it to the mooring system design of a semi-submersible crane and pipe-laying vessel (SSCV) in design environment conditions. Analyses are performed for the mooring system in operating condition and for the thruster assisted mooring (TAM) system in standing-by condition. Results of the analyses are used for the determination of mooring equipment, and mooring line strength check is carried out according to the partial safety factor format in Det Norske Veritas (DNV) code.