Abstract: Aiming at the ambiguous regulation mechanism of arc modes on the forming and properties of 316L stainless steel components fabricated by dual-wire wire arc additive manufacturing, dual-wire continuous deposition experiments for 316L stainless steel were carried out using cold metal transfer (CMT) and pulse arc modes under constant wire-feeding speed and welding traveling speed. The effects of arc modes on the macro-forming quality, microstructure and mechanical properties were systematically investigated by means of macroscopic morphology observation, metallographic examination, EBSD crystal orientation analysis, hardness, tensile and impact performance tests. The results show that the CMT mode delivers a heat input of 84.46 J/mm, presenting favorable forming quality with uniform layer patterns and no pores or cracks. For the pulse mode with a heat input of 112.31 J/mm, overheating of the molten pool gives rise to metal flowing, interlayer mixing and collapse defects. Columnar dendrites growing along the deposition direction are formed in both modes. Benefiting from a higher cooling rate, the CMT mode produces finer grains and a strong 001<100> cubic texture, with the fraction of low-angle grain boundaries reaching 97.9%. By contrast, grain coarsening and weakened texture intensity occur in the pulse mode, and the fraction of high-angle grain boundaries rises to 55%. Owing to the grain refinement strengthening effect, specimens fabricated by CMT mode achieve higher hardness and tensile performance, and all tensile indicators satisfy ASTM A240/A240M 2020 requirements. The pulse mode specimens possess superior longitudinal impact absorbing energy due to the high fraction of high-angle grain boundaries, whereas their yield strength and elongation fail to meet the standard. The CMT mode can guarantee satisfactory comprehensive mechanical properties under high-efficiency deposition, which provides support for arc-mode selection in dual-wire WAAM of 316L stainless steel.