[en] A method of determination for gallium in materials containing plutonium by diode array spectrophotometry is reported. In HCl medium, Pu was reduced to Pu(Ⅲ) completely by hydroxylamine hydrochloride. The Zerolit-FF anion exchange resin was used to separate and enrich gallium (Ⅲ). In NaAc-HCl buffer solution (pH=1.8 ± 0.1), gallium reacted with XO producing a new complex, then measured the absorbency at 540 nm, and corrected the background at 590 nm. The method has been applied, the results obtained were satisfactory with the recovery and the relative standard deviation of 95%-98% and less than 2% respectively. (authors)