The cylindrical floating production storage and offloading unit (FPSO) is a new type of offshore engineering equipment, which has been gradually applied to the development of the global offshore oil and gas resource. The motion response characteristics of a cylindrical FPSO suitable for the development of deepwater oil and gas fields in the South China Sea has been studied based on the three-dimensional potential flow theory and the Morison equation. The wet surface model and the hydrodynamic calculation model of the cylindrical FPSO are established by SESAM software to calculate the frequency domain motion response characteristics of the cylindrical FPSO in waves. The pitch, roll and heave motion responses of the cylindrical FPSO are compared with those of the ship-shaped FPSO with similar deadweight. The results show that the motion characteristics of the cylindrical FPSO are better than those of the ship-shaped FPSO. The heave motion responses of the cylindrical FPSO are also investigated for the cylindrical FPSO with different hull diameters, bilge box diameters, hull drafts and return periods of environmental conditions. The results can provide references for the overall design of the cylindrical FPSO.