In order to analyze the weld stress distribution of the single point base of a Submerge Turret Production (STP) system in Hainan under the operation condition, the mooring force of the single point mooring system is calculated based on hydrodynamic software, and the finite element analysis on the welds of the single point base is performed. By the comparison between the numerical analysis results and the practical monitoring data, the effects of the incompatible displacement between the single point base and the STP deck on the weld stress distribution is discussed. The analysis results are intended to provide experience and technical support for the design optimization of the single point caliper base.