Abstract: Heat treatment process experiments of 2209 duplex stainless steel were carried out to study the influences of solution temperature, solution time, tempering temperature, tempering time and other process factors on the mechanical properties and corrosion resistance of 2209 duplex stainless steel. On this basis, the microstructure of the sample under optimized heat treatment was analyzed to explore the mechanism of improving material properties. The results show that the order of influence of all factors on the mechanical properties and corrosion resistance of 2209 duplex stainless steel is solution time, solution temperature, tempering temperature, and tempering time. With the increase of solution temperature and solution time, the self-corrosion current density of 2209 duplex stainless steel decreases while the material's corrosion resistance gradually improves. The optimal heat treatment process for wire arc additive manufacturing 2209 duplex stainless steel is 1 000 ℃×0.5 h solution and 400 ℃×2 h tempering. The material's mechanical properties and corrosion resistance are improved under the optimized process, and the yield strength, tensile strength, elongation after breaking, self-corrosion potential and self-corrosion current density of 2209 duplex stainless steel are 568, 747 MPa, 58.53%, 0.21 V and 6.056 4×10⁻⁶ A•cm⁻², which can meet the performance index requirements of marine propellers. The heat treatment can increase the solid solubility of alloying elements in the 2209 duplex stainless steel structure in austenite, promote the full integration of alloying elements into austenite, and enhance the solid solution strengthening effect.