Abstract: Agrobacterium rhizogenes agropine type strains 15834, A₄ and mannopine type strains 8196, K599 are used to transform cotyledons and hypocotyls of Glycyrrhiza uvalensis. The results show that all the other strains induce hairy root clones except K599. The transformation efficiency of strain 15834 is the highest among the three strains, and the hypocotyl transformation efficiency is higher than the cotyledon's. Histological observation show that four days after infection, the cells outside vascular bundle sheath, especially the cambium cells redifferentiate to form root primordia, and the intact hairy roots form after about 8 days. The hairy root grow extensively on hormone-free medium. High voltage paper electrophoresis detected agropine and mannopine in the hairy roots. The results demonstrate that the opine synthase gene coded by Ri T-DNA has transferred, integrated and expressed in transformed tissues.