ATP content of cultured callus and hairy root introducted by Ri plasmid of Panax ginseng C. A.Mey was detected by bioluminescence. The result showed that ATP content in hairy root is obviously higher than that in callus within a growth cycle. The highest ATP content in hairy root is 26. 6×10 -12 mmol g ( fresh weight) , while ATP in callus is 2. 68×10 -12 mmol g ( fresh weight) . Total saponin content in hairy root reaches 2. 486% ( dry weight), while the saponin in callus is 1. 105% ( dry weight) . The hairy root inducted by Ri plasmid has vigorous ability in secondary metabolism for ginseng saponin synthesis.