<p>The internal compactness is a key indicator for evaluating the quality of castings, and porosity defects will seriously impair the performance of castings. This study investigated the synergistic effect of submerged gate filling and mechanical vibration. Comparative experiments were conducted on ZL114A aluminum alloy castings using a cubic connecting block as the test model. The casting processes were evaluated in terms of mold filling behavior, solidification characteristics, and final product quality. The results showed that different filling methods had significant impact on the melt flow, thermal distribution, solidification process, and final casting quality. Among them, the casting obtained by the combination of submerged gate filling and mechanical vibration method was the best. The submerged gate was lifted synchronously as the liquid level rose steadily. The molten metal was continuously poured into the mold through the submerged gate, which can optimize the flow filed and thermal distribution of the melt, improve the solidification process of the casting, and enhance the feeding efficiency. After applying mechanical vibration, the melt flow and feeding efficiency was further enhanced. Based on the synergistic effects of submerged gate filling and mechanical vibration, it was beneficial to obtain high-quality castings with dense solidification structure.</p>