Contents of four main kinds of flavonoids (flavonols, flavanols, proanthocyanidins and anthocyanins) and total flavonoids were detected in ‘Summer Black’ grape peel during the berries development. Expression patterns of genes involved in the flavonoids biosynthesis were also tested correspondingly. The highest flavonols content was detected in 21 days after full bloom (DAFB) and 31 DAFB (0.195 mg/g and 0.185 mg/g, respectively), then decreased markedly with berries growth and reached the lowest level (0.009 mg/g) in 52 DAFB. This was followed by a continuous rise until berries mature. Flavanols and proanthocyanidins have similar change patterns. Both of their content increase rapidly from 21 to 42 DAFB, reaching the highest level which were 3.238 mg/g and 8.604 mg/g respectively, then followed by a clear decline until the lowest level in 80 DAFB. Anthocyanins content was detected till 42 DAFB, then increased rapidly with berries development and reached the highest level (9.664 mg/g) at mature. Flavonoids content descended from 21 to 31 DAFB, then increased rapidly and reach highest level (18.723 mg/g) in 42 DAFB, followed a decline until berries mature. The relative expression level of flavonol synthase (FLS) was lower before veraison, then increased obviously and decreased again near maturity, which was not consistent with the changes of flavonols contents. Relative expression level of leucoanthocyanidin dioxygenase (LDOX) and UDP-glucose: flavonoid-3-O-glucosyltransferase (UFGT) increased gradually from veraison and reached the highest in maturity and were consistent with the content changes of anthocyanins. Relative expression level of leucoanthocyanidin reductase (LAR) and anthocyanidin reductase (ANR) decline continuously during the development of berries, which were consistent with the contents changes of flavanols and proanthocyanidins.