In this study, the relationship between the structure and properties of commercial purity aluminium (AW-1199) was investigated by applying constrained groove pressing (CGP) method. The refinement of the coarse grain aluminium microstructure to submicrocrystalline size by large plastic strain at room temperature defined. The impact of various strains upon microstructure changes is investigated using transmission electron microscopy (TEM) and electron back scatter diffraction (EBSD). A mixture of subgrains produced by grains subdivision and polygonized subgrains formed locally due to dynamic recovery was found in the deformed aluminium. The tensile properties and resulting hardness are related to microstructural evolution induced by CGP. A substantial impact of straining upon the increasing in tensile strength was observed after the first pass. Further strain increase had an insignificant effect on tensile strength but was accompanied by ductility loss. The post deformation annealing effect was then explored with aim to increase the ductility. The results indicate that changes in strength and ductility may be related to formation of a bimodal structure.