The chemical components of different parts of Erigeron annuus were examined in order to use as a new functional food material. Nitrogen free extract contents of flowers, leaves, stems and roots were 53.15, 55.79, 36.71 and $42.61\%$, respectively. The contents of crude fiber in the stems and roots were similar, while those in leaves were lower than those in the flowers. Mineral components of Erigeron annuus were rich in Na $(19.55~33.78;mg/100;g),;K (49.95~89.80;mg/100;g);and;Ca(25.39~116.40;mg/100;g)$. Among the portions of Erigeron annuus Ca contents was slightly higher level in tile loaves than those of flowers, stems and roots. The major free sugars of Erigeron annuus were sucrose $(0.12~1.37\%),;glucose;(0.68~1.08\%);and;fructose;(0.56~1.66\%)$. The contents of total amino acid in Erigeron annuus were 2,509.74 mg/100 g in the flowers,2,630.95 mg/100 g in the leaves, 889.54 mg/100 g in the stems, and 1,201.41 mg/100 g in leaves. Abundant amino acids in the flowers and leaves were glutamic acid, tyrosine and proline. And abundant amino acids of stems were lysine, glutamic acid and aspartic acid, and its root were lysine, glutamic acid and proline, Organic acid components of Erigeron annuus were succinic acid $(4.78~19.72;mg/100;g),;tartaric;acid;(3.90~6.91;mg/100;g);and;citric;acid;(1.79~6.60;mg/100;g)$. Nine fatty acids in Erigeron annuus were identified and the major fatty acids were myristic acid $(18.05~20.18\%),;oleic;acid;(18.50~32.91\%);and;linoleic;acid;(18.02~29.87\%)$. Total flavonoid and phenol contents were higher in leaf and flower extracts than any other extracts.