The reactions between multi walled carbon nanotube graft polycitric acid (MWCNT-graft-PCA) and Ag+ and Pd2 + ions at 25 °C are investigated spectrophotometrically. Encapsulation of Ag (I) and Pd (II) on the surface of (MWCNT-graft-PCA) as a function of pH, sonication time and reaction time was studied. The results indicated that the absorbance increased until pH = 6 and pH = 8 for Ag and Pd respectively and then decreased. The effects of sonication time on the reactions were studied and 20 min was selected for both of reactions. Also the time of reaction between MWCNT-graft-PCA and (Ag, Pd) vs. absorbance was studied and the stirring time of 160 and 100 min was selected for these reactions respectively. Also knowing the number of light-absorbing species is a critical step for subsequent quantitative and qualitative solution equilibrium studies. Behind the number of various complexes formed the stability constants for the combination of MWCNT-graft-PCA (ligand L) with Ag+ and Pd2 + ions at 25 °C and variant pH, and various mole ratios are estimated by the SQUAD program.