In inner turret single point mooring (SPM) system, the swivel stack is composed of multiple sets of swivel, which are the core equipment for FPSO to achieve production logistics transmission, water injection development, underwater production system control, power and signal transmission. It is necessary to master the key technologies for the design, operation, and maintenance of SPM swivel stack by studying the operation load conditions of swivel stack. When the ship rotates, the sliding platform and structural support frame are driven by sliding beam integrated with ship to produce tangential motion. At this time, the swivel stack needs to bear various loads. The combined force generated by various driving loads will produce different motion trends compared to the frictional resistance experienced by sliding platform. Finally, beneficial operation and maintenance suggestions were proposed for in-situ operation of swivel stack through load analysis.