Abstract: 【OBJECTIVE】The effects of external cycocel and gibberellin on the biomass and production of flavonoids in Scutellaria baicalensis were investigated in order to provide reference for the feasibility of the application of external hormones to the cultivation of medicinal plants. 【METHOD】On the 26th day after treatments of 200mg/L cycocel and gibberellin respectively over the seedling leaves, plant morphology was studied; height of plants and weight of aerial and underground biomasses were measured; contents of flavonoids and lignin were determined with HPLC and acetyl bromide-UV spectrometry respectively. 【RESULTS】(1) Compared with control group, cycocel resulted in greener and thicker leaves, more flowers, longer blossom cycle, shorter internodes and thicker stems; gibberellin resulted in significantly higher plants, smaller and less green leaves, thinner stems and more sprouts. (2) Both hormones promoted the biomass of aerial parts and inhibited the root biomass. (3) Both hormones reduced the content of flavonoids in the root while elevated the content of lignin in the aerial parts. 【CONCLUSION】Both cycocel and gibberellin induce the carbon source of the plant to the growth and lignin biosynthesis of the aerial parts, and at the same time inhibited the biomass increase and flavonoid biosynthesis in the root of S. baicalensis. Therefore, they are not suitable for the cultivation of S. baicalensis, and other medicinal plants of which the roots or rhizomes are used as the medicinal materials.