This study investigated the influence of leaflet geometry on the hemodynamic performance of pulmonary valved conduits and optimized leaflet trimming parameters using a design of experiments (DOE) approach combined with in vitro hydrodynamic testing. In vitro hydrodynamic experiments were performed to validate the feasibility of the valved conduit. A computational model was then established based on the experimental setup. DOE was applied to systematically assess and optimize leaflet tailoring parameters. Fluid-structure interaction simulations showed that leaflet tailoring significantly affects hemodynamic outcomes. Reducing leaflet height improved conduit performance. At a cardiac output of 3.5 L/min, the optimized valve exhibited a 3.79% decrease in peak velocity, a 45.18% reduction in maximum equivalent strain, and a 66.57% decrease in coaptation area. These findings suggest that scaling down the free edge length relative to graft diameter and moderately reducing leaflet height may help reduce diastolic regurgitation caused by redundant leaflet overlap while lowering leaflet strain, thereby enhancing valve durability.