This study investigates the influence of unsymmetrical surcharge on the piles of a bridge located in a coastal soft soil area, aiming to elucidate the deformation characteristics of the piles. The impact of some key parameters, including soft soil properties and unsymmetrical surcharge, on pile deformations is evaluated through 3D finite element numerical analysis and parameter sensitivity analysis. The results show that unsymmetrical surcharge significantly influences the displacement of both the piles and the surrounding soil, with both being affected by the soil arching effect. The parameter sensitivity analysis reveals that Poisson's ratio of the soft soil, and the stiffness of the piles have minimal impact on horizontal displacement. In contrast, the elastic modulus, cohesion, and internal friction angle of the soft soil, as well as the height and slope of the unsymmetrical surcharge, have significant effects on the piles. When the unsymmetrical surcharge is applied parallel or perpendicular to the bridge, the parallel surcharge has a relatively minor impact on the pile. The horizontal displacement of the pile follows an exponential relationship with L/B, D/h, and B/d. A functional relationship can be established between these parameters to predict the pile's horizontal displacement.