Severe Plastic Deformation (SPD) is defined as metal forming process in which a very large plastic strain is imposed on a bulk process in order to make an ultra-fine grained metal. The objective of the SPD process is to produce light weight parts by using high strength metal for the safety and reliability of micro parts and for environmental harmony. In the current work, SPD techniques like Equal Channel Angular Pressing (ECAP), Accumulating Roll Bonding (ARB), Repetitive Corrugation and Straightening (RCS), High Pressure Torsion (HPT), Reciprocating Extrusion Compression (REC), Severe Torsion Straining (STS), Cyclic Closed Die Forging (CCDF), Super Short Multi-pass Rolling (SSMR), Cyclic Channel Die Compression (CCDC), Mechanical Alloying, Asymmetric Rolling etc., are reviewed.