PURPOSE: A method for ultra high-density artificial cultivation of Gastrodiae Rhizoma by using oak logs sprayed with nutritious liquid containing oak wood vinegar, unrefined sugar, calcium carbonate and water, and an optimized drainage structure is provided. It radically removes root rot and yields 3 time more than conventional methods. CONSTITUTION: After excavating soil to a depth of 50 cm from a ground surface and leveling the soil, oak logs(1) are spread on soil in 15 rows by an ultra high-density manner, spawn(2) is inserted between oak logs, Gastrodiae Rhizoma seeds(3) are spread thereon. The Gastrodiae Rhizoma seeds are covered with soil to a depth of 20cm or more after planting to make a ridge(4) which is covered with rice straw(5) and installed with a lightproof covering(6) to maintain a soil humidity of about 45%. In the process for preparing oak logs, oak logs are cut to 40cm and sprayed with nutritious liquid containing oak wood vinegar, unrefined sugar, calcium carbonate and water in a ratio of 8:1:1:90 at 100 to 104deg.C for 24hr.