In this paper the grain structure and mechanical properties of AISI-321 austenitic stainless steel subjected to 7 passes of radial-shear rolling at 1000 °С were investigated. The tensile strength (1076 MPa) and Vickers microhardness (322 HV) after 7 passes increased by 2.2 times and 2 times, respectively, relative to the initial annealed state (480 MPa, 160 HV). Ultra-fine grained structure (200-700 nm) formed in the bar section area from its surface to a depth of 0.25 of the radius. The transition zone is located in the area between 0.5 R and 0.25 R of the bar section. Anything deeper is a rolling texture. The 7-pass radial-shear rolling process is an effective way to form UFG structure and improved mechanical properties in AISI-321 austenitic stainless steel. Keywords: severe plastic deformation, ultra-fine grained structure, radial-shear rolling, microstructure, mechanical properties.