With sterile leaves of Ardisia crenata Sims by tissue culture as explants,we performed hairy root induction by using four kinds of Agrobacterium rhizogenes strains,named A4,ATCC15834,LBA9402,R1601,respectively.The investigation selected optimal media types,pre-culture time,infection ways,co-culture time,and the ability of A.rhizogenes on hairy root induction.The study showed that 1/2 MS was the better medium for sterile leaves on hairy root induction,and hairy root induction rate was the highest (31.87%) under pre-cultured 2 d and co-cultured 2 d.It was the best way for infection that put sterile leaves and bacteria which was supplied with AS (100 mg/L) co-shake under dark,28 ℃ and 180 r/min for 8 to 15 min.All of the four strains could induce hairy root on A.crenata Sims,but ATCC15834 was the most effective strain,and A4 followed it.For ATCC15834,A4,LBA9402 and R1601,the ability of hairy root induction on A.crenata Sims was declining in turn.It demonstrated that T-DNA on Ri plasmid of A.rhizogenes had been integrated into the genome of the host cell successfully through molecular identification by PCR.