Abstract: The superplasticity mechanism of duplex stainless steels was studied mainly by means of crystallography. On this basis, the Electron Back Scatter Diffraction (EBSD) system was used to obtain the orientation distribution, Tango-mapping and Mambo-pole figures. Microstructural studies associated with transmission electron micrographs observed in the specimens during superplastic deformation suggest that superplastic process occurs mainly by strain-induced phase transformation and dynamic recrystallization, grain boundary sliding and grain re-orientation mechanism.