This research was carried out to clarify effects of cultural condition on the content of Alisol B-monoacetate, whose function is antihypercolesterol in blood, and yield in Alisma Rhizomes. When the corm part of Alisma Rhizomes was extracted by shaking extraction at $25^{circ}C$ and reflux extraction at $40^{circ}C$ to $100^{circ}C$ four times, the total content of Alisol B-monoacetate was 0. 402%, 0. 425% and 0. 402% at $25^{circ}C$, $40^{circ}C$ and $60^{circ}C$ respectively. The recovery rate was 97% by three times extraction at $25^{circ}C$, and 96% and 97% by three times extraction at $40^{circ}C$ and $60^{circ}C$ respectively. When the corm was harvested on Oct. 30, the content of Alisol B-monoacetate was 0. 46% but it was increased to 0. 71% on Nov. 30. In the case of Oct. 30, the corms of $S(4{sim}14g; FW)$ size were determined to contain the highest level of Alisol B-monoacetate (0. 53%), and the content was decreased as the corn size was increased. This tendency was also adopted on Nov. 30. On the other hand, the content of crude protein and starch was changed rarely by the period of harvest. When the planting depth was $0{sim}1cm$, the yield was the highest as 206kg/10a, and the yield was decreased as the planting depth was deep. The variation of the content of Alisol B-monoacetate was small as 0. 33% to 0. 39% by planting depth. From the above results it could be concluded that the optimum time for harvest of Alisma Rhizomes is Nov. 30 and the optimum planting depth is $0{sim}1cm$.