The orthogonal experiment was used to determine the optimization extraction condition of polyphenols from black and fresh Jerusalem artichoke. The optimal conditions were ethanol concentration 55%, the material solvent ratio 1∶ 35g/mL, temperature 85℃, and time 45min. Under this condition, the polyphenols extraction yield of black Jerusalem artichoke was 6.41mg/g while the extraction yield of fresh Jerusalem artichoke was 1.13mg/g. The results also showed that the antioxidant activities had relevance with polyphenols contents and a positive correlation between polyphenols contents and ferric reducing antioxidant power was obtained (R=0.9946). Polyphenols from black Jerusalem artichoke had higher DPPH scavenging ability, hydroxyl radical scavenging ability, and ferric reducing antioxidant power, which were 1.08~1.54 times, 1.02~1.28 times, and 2.56~3.98 times higher than fresh Jerusalem artichoke.