This study was conducted to elucidate the effects of green manure crop on growth characteristics and saponin contents of Platycodin grandiflorum Ridix roots for organic farming. Rye, hairy vetch and rye+hairy vetch were cultivated as green manure crops with several different methods before transplanting P. grandiflorum Radix. In root width and number of fine-roots, when the highest scores (23.9 ㎜, 25.7) was recorded in rye pre-cultibated plot in 2^nd year cultivation. Fresh weight of the Platycodin grandiflorum Ridix root was no significant difference among the different green manure crop treatments, but fresh weights of the Platycodin grandiflorum Ridix root of all green manure crop treatments were higher than that of control. The total content of saponin was highest detected in Platycodin grandiflorum Ridix roots of the hairy vetch plot (1,106 ㎎/100 g) and rye plot (1,693 ㎎/100 g) in 1^st and 2^nd year cultivation, respectively. Therefore, we confirmed that precultivation of the green manure crops showed significant differences in the growth characteristics and saponin contents of the Platycodin grandiflorum Ridix root, and growth and saponin contents in the Platycodin grandiflorum Ridix root of rye precultivated plot was much higher in 2^nd year cultivation than 1^st year cultivation.