Abstract: Considering the uncertainties in the load-bearing capacity coefficients of rigid piles, flexible piles, and inter-pile soil, this study took the Baiteng Sluice Project in Zhuhai City as an example to proposed both a standard calculation method and an improved calculation method for determining the composite foundation bearing capacity of rigid-flexible pile combinations. The methods focus on rationally determining the actual load-bearing capacity adjustment coefficients for rigid piles, flexible piles, and inter-pile soil. Results demonstrated that the characteristic values of vertical bearing capacity (actual measured value) for single piles in rigid-flexible pile foundations ranged from 620 kN to 638 kN during the test, which closely matches the improved calculation value (621.7 kN) for composite foundation bearing capacity. After application in the Baiteng Sluice engineering design, the project has been functioning well for years. This research results can provide a reference for hydraulic engineering designs in deep soft soil foundations.