Abstract: The paper exp lored the possibility of hairy root occurrence of peony induced by Agrobactrium rhizogenes.It showed that R1000 had the highest hairy root inducement with a hairy root rate of 35% , whereas strains A4,MSU-2 andMT232 had little difference in hairy root occurrence. Infect conditions had great influence on hairy rootinducement, and the better ones are: acetosyringone concentration, 30 mg·L-1 ; infection time, 15 minutes; andculturing conditions of strains, temperature 28 ℃, 28 hours shaking culture under dark environment with shaking.Pre2experiment on tissue culture system of peonywas conducted, and got bettermedium composition as: WP + 6-BA0. 5 mg·L-1 + IBA 0. 1 mg·L-1 + GA3 0. 5 mg·L-1 for base buds, andMS + 6-BA 2. 0 mg·L-1 + IBA 0. 1mg·L-1 + GA3 0. 5 mg·L-1 for stem segments.