Abstract: Butt welding of SiCp/2009 Al MMCs with a 1.3 mm preset gap was achieved by the oscillating laser filler wire welding process. The influence of wire feeding speed on weld formation was investigated, and the microstructure characteristics, mechanical properties, and fracture characteristics of welded joints under the optimal wire filling amount were systematically analyzed. Results indicate that when other welding process parameters are constant, an appropriate wire feeding speed can effectively fill the preset gap. Wire feeding speeds that are too low or too high lead to poor weld formation, and the microstructure of the welded joints exhibits heterogeneity. Compared with the base metal, the size of Al₂Cu in the heat-affected zone decreases, but its quantity increases due to the influence of the welding thermal cycle, while only a small amount of SiC and Al₂Cu particles exist in the weld seam. Because the dilution rate of the base metal decreases, and more laser energy is used to melt the ER5356 filler wire, the dissolution degree of SiC is reduced, which effectively inhibits the formation of Al₄C₃. Tensile test results show that the tensile strength of the welded joints reaches 68.9% of that of the base metal, and brittle fracture occurs near the fusion line of the specimen. The main reason for the fracture is that the formation of void-like defects reduces the effective load-bearing area at this location.