Abstract: Focusing on the manufacturing of ultra-large excavators, a key task for domestic host enterprises, welding positioners play a crucial role in the fabrication of structural components for these machines. This paper takes the welding positioner for the boom of an ultra-large excavator as the research object, deeply analyzing the structural characteristics, process requirements, and key technical parameters of the boom. Based on this analysis, an innovative design approach for the welding positioner is deduced. Through precise structural design, this welding positioner successfully achieves optimal welding postures for both the front and rear sections of the ultra-large excavator boom in all directions. Practical applications have shown that this welding positioner not only achieves remarkable welding results with a high welding yield rate but also occupies a small footprint, effectively enhancing production efficiency. The research findings provide valuable references for the design of process equipment for ultra-large excavators and are of great significance in promoting the independent development of high-end construction machinery equipment.