By setting surface subsidence monitoring instruments in a large area of the loading site, the on-site monitoring lasted 3 years, and the analysis was made on the deformation characteristics of coastal hydraulic fills soft ground subsidence under large area heaped load. It is revealed that the deformation characteristics of soft ground under large heaped load are different from those under normal load and the soft ground deformation settlement law of large area heaped load conditions is summarized. By the use of numerical methods, the foundation deformation law is simulated and the foundation failure mode is analyzed, the numerical calculation results and the field monitoring results have a good coherence. Under 400kPa heaped load force, the maximum settlement value is approximately 1.6m.