To address the operational efficiency reduction caused by sediment accumulation in the bottom corridor of storage tanks, the influence of sediment moisture content on the flushing characteristics of a hydraulic self-cleaning system in storage tanks was investigated through physical experiments, as well as its coupling effects with sediment thickness and flushing flow rates. The results demonstrate that the scouring rate exhibits a nonlinear parabolic relationship with sediment moisture content, with an optimal moisture content range of 12%-20%. Low moisture content (＜12%) inhibits scouring due to enhanced interparticle cohesion and shear strength, while high moisture content (＞20%) reduces the scouring rate owing to increased self-weight. Sediment thickness significantly affects scouring efficiency, with medium moisture content (12%-20%) showing the weakest sensitivity to thickness variations. The positive correlation between flushing flow rate and scouring rate is affected by moisture content, and the effect of increased flow rate under medium moisture content is the most significant. Structural optimization of corridor sidewalls eliminates diamond wave interference, improving the scouring rate by 15.34%-37.83% across all moisture content levels and transforming scouring morphology from wavy to strip-shaped patterns.