Abstract: In this paper, the methods of separation macro-lridium and determination of micro-rhodium have been studied.By using home-made 15% of tri-(6,7,8)alkyl-phosphine oxide-benzene solution for extracting in 4N HCl, we have been successively separated the macro-lridum apart from micro-rhodium.The extraction rate for once lies in the range 97-99%.We have also found the optimum electrolytic system of 0.1N HCl-0.02Nethylene diamine-2.5×10^-6M HgCl₂(pH= 1.4) for determination of micro amount of rhodium (Ⅲ) by anodic stripping voltammatry (ASV) on glass carbon electrode.The limit of detection as low as to 10 ppb may be achieved.