An adventitious root formation protocol from Smilax china L. was established for in vitro production of dioscin, a steroidal saponin having various bioactivities such as anticancer, antifungal, antiviral, and antiobesity. Optimal medium for root initiation from leaf explant was MS medium containing 30 g·L-1 of sucrose supplemented with 1.0 mg·L-1 kinetin + 2.0 mg·L-1 NAA. The induction of adventitious roots from in vitro initiated root segments was most favorable to MS liquid medium with 0.1 mg·L-1 kinetin + 2.0 mg·L-1 NAA. Among the 20 different adventitious roots originated from different plants, strain No. 10 was selected based on production ability of dioscin, and its stability through the successive suspension culture. The maximum growth stage of adventitious roots was noticed at 5 weeks after subculture while that of dioscin production in the adventitious root was at 7 weeks after subculture in suspension culture system. These results provide that suspension culture of adventitious roots of Smilax china L. have a potential for in vitro mass production of dioscin.