Abstract： The effects of exogenous plant hormones and activated carbon (AC) on the development of saffron corms in vitro were studied. Both hormone concentration and AC level influenced corm induction. When 1/2 Murashige and Skoog medium was supplemented with low concentration of hormones, corms were induced quickly while big corms formed slowly at high concentration of hormones. The addition of AC decreased the concentration of free hormones and the time of corm development significantly, while the slow release of hormones raised corm size. In the medium with optimal 0.5 g/L AC, high induction rate (85.7%) and big corms (0.53 g average weight) were obtained in 5 weeks when 5 mg/L naphthalene acetic acid and 5 mg/L 6-benzylaminopuine were added to the medium.