This study optimized the integrated die-casting of an aluminum alloy longitudinal beam and tower component using no heat-treated aluminum alloy. Leveraging material properties and part geometry, a pouring system was designed and refined through mold flow analysis. This optimized the velocity, temperature distribution, and air entrapment to reduce defects like shrinkage porosity. The optimized pouring parameters were 695 °C melt temperature, 210 °C initial mold temperature, and 4.9 m/s shot speed. This reduced shrinkage porosity by 10.4% versus the original design. Die-casting trials with the optimized pouring system produced defect-free castings. The critical load-bearing section of the die casting had a yield strength of 184 MPa and elongation of 10.9%, which can meet the production requirements. In summary, based on the optimization of pouring system by mold flow analysis, by developing the integrated die casting process for aluminum alloy. Not only the defects are eliminated, but also the castings with sufficient mechanical properties are produced.