In this work, the formation conditions of 2.2’- diamincarbanilid (ODAK) - copper (II) complex (λ_max = 395 nm ) were studied and stability constant were determined spectrophptometrically. There was observed the effect of oxygen on the complex formation. The reaction rate was increaed as a function of [O₂] ^0,5. Th composition of complex were determined as Cu/ODAK = 1/1 at pH = 6.70 by Job’s method of continious variation. There was the pH effect on the complex formation and the reaction rate was increased as a function of [H^*]^-1 or [OH-]. The stability constant of complex was determined as log K= 3.6023 by using of the ligand excess method and log K = 3.6015 by using the equal absorbed solutions method. The rate equation is V = K [Cu ²⁺] [ODAK] [O₂]^½ [OH-] at pH= 5,84 - 6.99 range. It was conluded that the composition of the indigo coloured complex which was precipitated at about pH= 8.0 was [Cu(ODAK)(OH)2] and it was changed by CO₂, NH₃ and H₂0 evaluation to the final product. The final product was 2,2’- diaminodiphenylamin-copper(I) complex ([Cu(C₁₂H₁₃)]OH ). Keywords :