Abstract: Change characterizations of the contents and compositions of the anthocyanin and the chlorophyll were studied in 4-year-old‘Northland’blueberry as materials during leaf color transformation in autumn. With the change of leaf color，the total amount of anthocyanin increased，and the greater the increase in the later stages. However，the total amount of chlorophyll decreased with larger decline in the initial stage. Five kinds of anthocyanins were detected in the full green leaf. Along with the leaf color transformation，more anthocyanidins were detected. Eleven kinds of anthocyanins，which belong to 4 kinds of cyanidins：delphinidin，petunidin，malvinidin and peonidin，were detected in the red leaves. Among all the anthocyanins，delphinindin-3-O-arabinoside，petunidin-3-O-galactose and petunidin-3-O-glucose were three kinds of main anthocyanins，which co-led the trend of total anthocyanins. Intrestingly，along with the transformation of leaf color，the total amounts of the delphinidin and petunidin increased，while their ratio remained unchanged. The trend of the Chl.a and Chl.b contents were consistent，in which the Chl.a had higher content and larger change range than Chl.b. The comprehensive analysis showed that the increase of anthocyanin accumulation and the decrease of chlorophyll accumulation were the key factors of leaf color transformation. The delphinidin and petunidin were the main ancyanidins，and their contents and ratio might determined the“red”color of leaf. During leaf color transformation，three kinds of anthocyanidins were mainly accumulated：delphinidin-3-O-arabinoside，petunidin-3-O-galacoside and petunidin-3-O- glucoside，affecting the trend of total amount of anthocyanins，the main pigment ratios and the leaf color，furtherly.

Key words: blueberry, leaf color, anthocyanin fraction, chlorophyll