Under physiological conditions, spectroscopic techniques as well as molecular docking simulation have been used to investigate the binding interaction mechanism between Cu(II) complex containing Pyridine-2,6-dicarboxylic acid (PDCA) and Diethanolamine (DEA) ligands, [Cu(DEA)(PDCA)] and human serum albumin (HSA). UV spectral changes of protein in the presence of the Cu(II) complex suggested the formation of a Protein-Cu(II) complex conjugate with specific new structure. The Cu(II) complex quenches the intrinsic fluorescence of the HSA