Abstract: The chlorogenic acid extract of dandelion and sunflower seed meal were selected as test materials, and antioxidant activities of chlorogenic acid form dandelion and sunflower seed meal were determined using FRAP ferrous ion reducing capacity.The synergistic antioxidant activities of chlorogenic acid from dandelion and sunflower seed meal were evaluated on IC₅₀ values for developing green and efficient natural antioxidants.The results showed that FRAP ferrous ion reducing capacity of chlorogenic acid from dandelion and sunflower seed meal was high level of 1.11 and 1.09 at pH 4.0 and 37 ℃.The compound of chlorogenic acid from dandelion and sunflower seed meal increased in FRAP ferrous ion reducing capacity with synergistic antioxidant effect.