Nowadays, the deep water in China is in the early developing stage, and it adapts for floating drilling, production, storage and offloading structure (FDPSO), which integrates the functions of drilling, production and storage. FDPSO can reduce much expense for early development of oil field. In this paper, a new-style eight-square FDPSO is studied. Based on the complex environment in deep water and the load cases, the global structure model is built. According to the three-dimensional potential flow theory and spectra-based analysis method, the wave loads are calculated and design wave parameters are decided. By transferring the design wave loads to global structure model, the structure stress is obtained. The calculation results can provide theoretical reference for the design of FDPSO working in the oil fields of deep water.