The microstructural evolution and softening mechanism of 2205 duplex stainless steel during hot deformation were investigated by high temperature compression tests at different temperatures ranging from 850°C to 1250°C with different strain rates of 0.1 s^-1, 1 s^-1 and 10 s ^-1. The microstructures after hot compression were characterized by means of optical microscope and scanning electron microscope equipped with an electron back-scattered diffraction (EBSD) system. The results show that the peak stress and the corresponding strain decrease with the increasing temperature. The stress-strain curves show typical characteristics of dynamic recrystallization or dynamic recovery under different hot compression conditions. The transition temperature at which the stress-strain curve changes from dynamic recrystallization type to dynamic recovery type increases from 1150°C to 1050°C as the strain rate increases from 0.1 s^-1 to 1 s^-1 and 10 s^-1. The phase transformation of ferrite to austenite was dominant in the microstructure of 2205 duplex stainless steel when deformation temperature increased from 850℃ to 950℃. With the increasing temperature, the strength difference between ferrite and austenite decreased gradually, and the transformation from austenite to ferrite was predominant in the microstructure of 2205 duplex stainless steel when the deformation temperature was above 950℃. Ferrite and austenite in the microstructure of 2205 duplex stainless steel exhibited different softening mechanisms under the hot compression conditions adopted in this work. Ferrite was softened by dynamic recovery and dynamic recrystallization, while austenite with lower stacking fault energy was softened by a limit degree of dynamic recovery.