This study was conducted to investigate the weight of crown part effect on growth and bolting response of Ostericum koreanum Kitagawa. Bolting rate with crown part weight was represented 0%, 0%, 4.1%, 12.9%, 25.1%, 34.9% corresponding to each crown part weight 5 g, 10 g, 20 g, 30 g, 40 g, 50 g. The heavier the crown part weight was the higher the direction rate rose and the flowering time came earlier. The dried root amount was the highest at 30 g and crown part number, the length of root, and crown diameter showed all the highest figures at 30 g. The relation between amount per 10 g and outcrop weight increased on secondary regression formula as weight increased and reached its peak at 29.7 g and then decreased over 29.7 g.