Abstract: The fluid swivel is a key component of the single point mooring system for offshore oil and gas development, and it is one of the components that need to be home made urgently. The flow field simulation method is used to analyze the flow field in the swivel cavity. The velocity and pressure distribution are studied. Combined with the requirements of the fluid swivel on fluid impact force and sediment deposition, the optimization scheme for the cavity shape of the prototype of a domestically produced swivel R&D project is put forward. Besides, the strength of fluid swivel is checked by finite element simulation analysis method. The results can provide references for the cavity and component design of swivel.