Abstract: The variation of welding spatial positions directly influences droplet transfer and the force state of the weld pool, thereby affecting the performance of welded joints. Understanding the influence rules of spatial position on joint performance and developing appropriate welding processes are essential for achieving reliable all-position welding in large-scale and complex engineering structures. The influence of spatial position changes on droplet transfer and weld pool forces was first analyzed. Meanwhile, the correlation between welding positions and process selection was discussed, and the effect of different welding processes at various positions on joint performance was summarized. Furthermore, the effect of welding position on both external weld morphology and internal mechanical properties was elaborated. This indicated that welding position variation, under specific conditions, should not be regarded merely as a passive compromise dictated by production requirements, but rather as an active approach for performance optimization. In addition, new processes and methods for optimizing all-position welding were reviewed from both process improvement and auxiliary equipment. Finally, an outlook on the influence of welding spatial positions on joint performance and the potential future research directions was provided.