This study was conducted to investigate the effect of horticulture on hand function and cognitive ability of the old age with serious brain diseases. This study was intended for the inpatients in a geriatric ward, K hospital located in Gumi-si, Kyeongsangbuk-do, for dementia or cerebral apoplexy caused by brain diseases. Patients were divided to 7 of experimental group and 4 of control group. Horticulture program included flower arrangement in the first half and plant culture in the later half. As a result horticulture program test, Hand function showed significant development on both hands from 57.42 to 82.57 (p=.001) on the right hand, from 62.50 to 90.58 (p=.001) on the left hand. Change of cognitive ability show as follow. Communicational problem and senile infirmity of the patients with serious brain diseases made many difficulties. The numeral value, therefore, did not show significant development due to high individual deviation. As a result, horticulture program is effective for development of cognitive ability and hand function for the old age with serious brain diseases. Therefore, the more systematic horticulture program in the long view is expected to help the old age with serious brain diseases to raise the quality of life and give them effective affect.