Abstract: In order to solve the problem of insufficient hot processing of Gd-containing duplex stainless steel, the 2%Gd duplex stainless steel was taken as the research object and carried out thermal simulation compression experiments at different temperatures to study the thermal deformation behavior and microstructure evolution of Gd-containing duplex stainless steel. The Gleeble-1500D thermal simulation testing machine was used to conduct a single-pass thermal deformation test with a deformation of 50% on the Gd-containing duplex stainless steel. According to the true stress-true strain curve, the thermal deformation activation energy Qd of the alloy was calculated, and the constitutive equation was established. This equation can provide a theoretical basis for the selection of high temperature thermal deformation equipment and the prediction of high temperature deformation resistance. It also has a certain guiding significance for the control of material properties and the optimization of processing technology. At the same time, the microstructure after thermal deformation was analyzed to explore the effect of rare earth element Gd on the thermal deformation behavior of Gd-containing duplex stainless steel. The results show that the dynamic softening mechanism of the alloy is mainly dynamic recrystallization during hot deformation. Large-sized ferrite grains recrystallize to form fine equiaxed crystals, while part of the austenite grains grow along the rolling direction and become smaller in size. The alloy contains two precipitation phases Gd-containing, namely M₃Gd phase and M₁₇Gd₂ phase (M=Fe, Cr, Ni), both of which have a hexagonal structure, and exist in the grain boundary or grains. The M₁₇Gd₂ phase has little effect on alloy workability. Compared with M₁₇Gd₂, the M₃Gd phase on the grain boundary has a greater influence on the matrix. The brittle M₃Gd phase destroys the continuity of the matrix and cannot deform synergistically with the matrix structure. A large number of brittle M3Gd phases reduce the thermoplasticity of the alloy and leads to intergranular cracking of the alloy during hot working. The precipitation temperature of the M3Gd phase is about 1 050 ℃, and the higher the temperature, the more the precipitation of M₃Gd phase. This is consistent with the results of the macrophotograph after compression of the sample. Above 1 100 ℃, the sample will all have cracks, and the higher the temperature, the more cracks on the samples. Therefore, the hot working temperature of the alloy is controlled not to exceed 1 050 ℃. Combining the calculated thermal processing diagrams and scanning photos, it is found that processing instability areas will occur when the alloy is processed at a high strain rate, and there will be micro cracks in the sample. Therefore, it is determined that the better suitable thermal processing process range for the alloy is a strain rate of 0.01-0.1 s^-1, and the deformation temperature is 950-1 000 ℃.