Structure and properties of Cu in dependence on strain (from ε ∼ 0.9 to ε ∼ 15) during multi‐axial compression processing at room temperature was investigated. The evolution of dislocation structure, misorientation distribution and crystallite size were observed by using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) equipment with electron back scattered diffraction (EBSD) facility. The mechanical properties of yield strength (YS), ultimate tensile strength (UTS) and uniform elongation was performed on MTS QTest/10 machine equipped with digital image correlation method (DIC).The structure–flow stress relationship of multi‐axial compression processing material at strains ε ∼ 3.5 and ε ∼ 5.5 is discussed. It is found that processing does not produce any drastic changes in deformation structure and the microstructural refinement is slow. These results indicate that dynamic recrystallization plays an important role during multi‐axial compression process in this range of deformation (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)