Abstract: The dynamic performance of a new deep-water octagonal floating drilling production storage and offloading unit (FDPSO) is investigated in this paper. The model is constructed using a scale-down ratio of 1:60. Two types of heave plates, a single-layer and a double-layer with varying spacing, are installed. Different tests, including free decay test, white noise test, and tests simulating wind and wave currents during one-year and one-century events, are conducted. These tests aimed to examine the motion performance of the floats and the impact of the heave plate on their motion. The results indicate that the single-layer heave plate has the smallest natural period of floating body movement and the largest dimensionless damping coefficient. For the double-layer heave plate, the increase damping effect and vertical panel drainage problem is selected as the optimal gap of 5m. The peak RAO of the hull when subjected to the double-layer heave plate with a spacing of 5m is greater than that of the single-layer heave plate instance. In general, the single-layer heave plate is more effective in reducing motion. It experiences less float motion, bollard force, and typical positional acceleration compared to the double-layer heave plate scenario with a 5m spacing, when subjected to the combined forces of wind and wave currents.