Abstract: To address the problem of severe local erosion of refractory materials in a blast furnace trough, a three-dimensional numerical model of the trough was established based on the volume of fluid (VOF) multiphase flow model and the standard k−ε turbulence model. The effects of different taphole inclination angles (0°–15°), diameters (60–80 mm), mass flow rates (7–10 t/min), and trough structures on the flow field and wall shear stress distribution were investigated, and a “wide-bottom deep-pool” optimized structure was proposed. The results show that erosion is jointly governed by the direct impingement of the jet on the trough bottom and the wall-attached shear of recirculating vortices on the side walls. The momentum distribution is relatively optimal when the inclination angle is 10°. Increasing the taphole diameter is most unfavorable for bottom erosion: when the diameter increases from 60 mm to 80 mm, the peak shear stress on the trough bottom increases from 32 Pa to 352 Pa, while sidewall erosion is weakened. When the mass flow rate increases from 7 t/min to 10 t/min, the jet impingement point shifts backward into the deeper molten iron zone, and the peak shear stress on the trough bottom decreases from 41 Pa to 17 Pa, while the sidewall shear stress remains stable at 12–15 Pa. The proposed "wide-bottom deep-pool" structure reduces the slope height and widens the trough bottom, shifting the high turbulent kinetic energy zone upward to the free surface and effectively weakening the intensity of the recirculating vortices. Under the condition of 7 t/min, the peak shear stresses on the bottom and sidewalls after optimization are reduced by 39.0% and 39.3%, respectively, and a consistent downward trend is also observed under other mass flow rates. The research results provide a theoretical basis for the long-life design of blast furnace troughs.