Abstract: The paper presents the determination of trace vanadium in ore samples by derivative spectrophotometry, based on the chromatogenic rection of diantipyryl (p-dimethylamino) phenylmethane (DADM) with vanadium (λmax=552 nm), in a homemade flow injection system. Two inflexion points of the derivative absorbancy (△A) could be obtained in one injection. The method provides linear dynamic range of 0~0.18 μg/mL for vanadium with sampling frequency of 110 injections per hour. The method has been applied to the determination of trace vanadium in ores with satisfactory results.