Abstract: Objective This paper aims to solve the problems of brittle intermetallic compounds, poor weld formation and porosity in aluminum/steel dissimilar welded joints. Methods This study used oscillating laser welding-brazing to optimize connection performance, improve weld formation quality, inhibit porosity and regulate interface structure. 2 mm thick 304 stainless steel and 6061-T6 aluminum alloy are used as base materials, and AlSi12 welding wire is used for butt welding. The weld morphology, section structure and interface layer characteristics of laser welding-brazing and infinite oscillating laser welding-brazing are compared, and microstructure of interface layer is analyzed by energy dispersive spectrometer (EDS). Results Oscillating welding significantly improves welds formation, reduces undercut defects, and achieves no porosity. The interface layer by laser welding-brazing consists of 18.2 μm thick three-phase structure with Fe₂(Al,Si)₅/Fe(Al,Si)₃/Al₈Fe₂Si. The interface layer by oscillating laser welding-brazing is reduced to 4.6 μm thick,and consists of Fe(Al,Si)₃/Al₈Fe₂Si dual-phase structure. The average tensile strength is 187 MPa. Conclusion Under the optimized parameters,the joint forming quality and mechanical properties by oscillating laser welding-brazing are optimal, which provides a theoretical basis for adaptive regulation of welding process parameters for aluminum/steel dissimilar materials.