More efficient and selective extraction systems are especially attractive in the solvent extraction process. A synergistic green solvent extraction system of vanadium(V) in a black shale acid leaching solution that uses a mixture of diisooctylphosphinic acid (Cyanex272) and trialkylamine (N235) is proposed. The effects of the volume ratio of extractant on vanadium extraction and the synergistic co-efficient (R) were studied. The vanadium extraction could reach 96.70% at conditions of 12% Cyanex272, 8% N235, a pH of 1.60, an O/A phase ratio O/A 1:2 and an extraction time 8 min. FT-IR spectra analysis indicates that the synergistic effects owing to the formation of hydrogen bonds N-H+ -O=P result in easier dissociation of the hydrogen ions in Cyanex272. In the extraction process, two kinds of vanadium species VO2+ and H2V10O284-, can both be extracted by an ion exchange reaction. Under optimal condition, a vanadium-rich solution containing 12.80 g/L and V2O5 product of 99.32% purity were obtained after three-stage extraction, three-stage scrubbing and three-stage stripping. The vanadium concentration in raffinate decreased to 5.69 mg/L and the impurities especially Fe, Al, P, Si were efficiently separated. The findings in this study could also give the inspiration for the recovery or removal of vanadium and other metal ions in different solutions.