The magnetic pulsed compaction, based on a pulsed magnetic field force action on conductors, is one of the effective methods of nanopowder compaction. In this book, the authors present a theoretical description of the magnetic pulsed compaction processes. The powder compaction is described within the continual approach of plastic hardened porous body. The increase of the powder yield stress is defined by the empirical laws of hardening, where free parameters are determined via experimental adiabatic curves of the uniaxial compaction.