Results are presented from an analysis of the nano-and magnetic domain structures of high coercive Sm(CoCuFe) 5 alloy using fractal geometry. Fractal dimension D f of the nano-and domain structures are determined at different stages of heat treatment. It is shown that D f ~ 2.08 corresponds to the nanostructure of samples with a coercive force of 7 kOe, while D f ~ 2.3 corresponds to the nanostructure of samples with a coercive force of 32 kOe.