With the rapid advancement of modern industry, the demand for high-performance materials has grown significantly. Titanium/duplex stainless steel composite plates, known for their exceptional corrosion resistance, demonstrate vast potential for diverse applications. In this study, a bimetallic composite plate comprising TP270C titanium alloy and SUS821L1 high-strength duplex stainless steel was fabricated using explosive welding. The microstructural characteristics of the composite plate interface were thoroughly investigated through metallographic microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD). Additionally, the welding quality was systematically evaluated. The results showed that the welded interface exhibited an intermediate structure between flat and wavy when the interface deposition energy was low. In contrast, the welded interface displayed a wavy structure at higher interface deposition energy. Element diffusion and grain refinement were observed in the regions adjacent to both interfaces. Complete recrystallization predominated in the welded interface, molten zone, and adiabatic shear band. Near the welded interface, titanium underwent partial recrystallization, while duplex stainless steel exhibited a combination of partial recrystallization and deformed grains. Localized thermal accumulation facilitated grain growth in the molten layer, whereas titanium particles encapsulated within the molten layer exhibited refined grain structures. Mechanical performance tests indicated that the sample with higher interface deposition energy achieved a 40.33% increase in shear strength and a 4.52% improvement in bending strength compared to the sample with lower interface deposition energy.