A number of activated carbon fibers (ACF) were prepared by activation with steam, Phosphoric acid, or Zinc Chloride. Their reduction-adsorption behavior for Pt(IV) was studied using scanning electron microscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy. The results show that Pt ions in solution can be adsorbed by ACFs and reduced to metallic platinum. The reduction-adsorption capacity of ACF for Pt could be greater than 200 mg/g. Generally, higher specific surface area or lower electrode potential produces a higher capacity. Most of the adsorbed platinum ions were reduced into metallic platinum, and about 25% of platinum atoms remained as Pt(II) or Pt(IV). XRD examination showed that the Pt particles on the ACF surface were crystallized when heated to 673 K.