Abstract: This article analyzes the bearing capacity of a shallow sea artificial island filled with silty fine sand foundation that has experienced subsidence and water seepage for more than 10 years of operation. Based on the results of spiral plate load tests, the relationship between the SPT’s blow count N’, DPT’s blow count N'₁₂₀ and foundation bearing capacity is studied. Empirical formulas are fitted, and on this basis, the current bearing capacity of the silty fine sand foundation is comprehensively analyzed to explore the long-term bearing capacity characteristics of the foundation. The results indicate that the artificial island foundation formed by silty fine sand is further compacted under long-term repeated hydraulic action, and its bearing capacity is improved, which is conducive to the safe operation of the site. However, due to its loose nature, it is prone to loss under hydraulic action, and inadequate anti-seepage measures may lead to engineering problems such as subsidence, hollowing out, and water seepage, affecting the safe operation of the site. Therefore, in response to the phenomenon of subsidence and water leakage in this project, anti-seepage measures such as in-situ solidification and curtain sealing need to be taken for treatment.