Abstract: A simple and rapid spectrophotometric method for the determination of chromium (Ⅵ) with 9-orthochloropheny1-2,3,7-trihydroxyfluorone (o-Cl-pF) has been investigated. This method is based on the formation of a complex in the hydrochloric and phosphoric acid medium (0.4N HCl+3N H₃PO₄).The complex has an absorption maximum at 497nm. The value of molar absorption cofficient is 2.33×10⁴at λ_515nm. Beer' s law is obeyed over the range 0-30μg/25ml of Cr.The two wavelengths for the determination of 0-10μg/25ml of Cr by using dual-wavelength method are 462 and 497nm. By using the proposed method, the Cr contents in alloy and metallic materials were determined with satisfactory results.