Abstract: Duplex stainless steels, characterized by a dual-phase microstructure of ferrite and austenite, combine high strength, good toughness, and excellent corrosion resistance, making them widely applicable in fields such as marine engineering, chemical equipment, and pressure vessels. Welding, as a critical step in their fabrication process, plays a decisive role in microstructural evolution and mechanical properties. This paper systematically reviews recent research progress on the mechanical properties of duplex stainless steel welded joints, with a focus on analyzing the microstructural characteristics of the base metal, heat-affected zone, and weld metal, as well as their influence on strength, toughness, and fracture behavior. It further summarizes the mechanisms by which key factors-such as secondary phase precipitation, thermal cycling characteristics, residual stress distribution, and filler metal composition matching-affect joint performance during welding. Studies indicate that microstructural imbalance and the formation of brittle phases induced by welding are the primary causes of mechanical property degradation. However, comprehensive joint performance can be significantly improved through process control, optimized filler metal design, and post-weld heat treatment. This review aims to provide theoretical foundations and engineering guidance for microstructural regulation and performance optimization of duplex stainless steel welded joints.