Transition metal form complex with ligand and this metal complexes play very important roles in biological system. Metal complexes is a branch of biological inorganic chemistry. This field has important implications in many other sciences, ranging form medicine to the environment. It is an interdisciplinary science. Scientists working in different areas of Chemistry, Biochemistry, Biology, Physiology, Agriculture, Physics and even Mathematics. Furthermore, studies of the roles of metal ions is biological system often involve development of relevant chemistry. The analysis of the representative species distribution curves shows that in the pH range 1-4 metal ion M(II) is the major species. In the pH range 4-7 for Cu(II) complex or above in case of Ni(II) complexes the species MA, ML, MAL exist, where M = Ni(II), Cu(II) and A = Diethylenetriamine (DET) and L = Oxalic acid, Tyrosin, Ethylenediamine, Glycine, alpha-Alaline, Phenylalanine, The percentage of the species MA 2 , ML 2 are very less. In the present study, the ligand A, are characterized by three p values. p 1 and p 2 corresponds to two -NH 2 protons and p 3 corrosponds to -NH proton. It is observed that for the metal ligand formation constant logK 1 and logK 2 , the difference (logK 1 -logK 2 ) is more in case of Cu(II) as compare to Ni(II). The logK value was calculated by using SCOGS computer program. The value of logK are more negative of Cu(II) complex compair to Ni(II) complex. So, the complex of Ni(II) is more stable than Cu(II) complexes.