Abstract: To address the complex horizontal loads and strict deformation control requirements for photovoltaic pile foundations in marine tidal flat environments, this study employs a numerical simulation approach to systematically investigate the deformation mechanism and bearing performance of PHC pipe piles under horizontal loading. The analysis focuses on the influence of three key parameters: wall thickness, embedded depth, and pile length. The results show that, at a horizontal load of 9 kN, increasing the wall thickness from 80 mm to 120 mm reduces pile top displacement by approximately 18%, demonstrating that enhanced wall thickness effectively increases bending stiffness and restrains displacement. When embedded depth increases from 6 m to 8 m, pile top displacement decreases by 27% to 40%, and the soil disturbance range is reduced by approximately 0.7 m to 0.8 m. This confirms that increasing embedded depth mobilizes greater soil resistance and is the most effective measure for controlling displacement and minimizing soil disturbance. In contrast, extending pile length primarily elongates the free segment above the mudline; under the same load, increasing pile length from 11 m to 13 m approximately doubles the pile top displacement. Therefore, pile length should not be relied upon for displacement control in design. Based on these parametric influence patterns and mechanistic insights, a coordinated three-parameter adjustment strategy centered on displacement control and a zoning design method accounting for hydrogeological variations in tidal flat areas are proposed. These findings provide references for the optimal design of photovoltaic pile foundations in marine tidal flats.