Growth and ecological differences of some important medicinal plants (Carthamus tinctorius, Astragalus membranaceus, Digitalis purpurea, Melissa officinalis, Anethum graveolens, Angelica gigas and Saururus chinensis) were observed at the different attitudinal sites of Mt. Halla in Cheju from 1997 to 1998. Growth of all medicinal plants was generally higher in the northern slope parts than in the southern slope parts. But at 50m above the sea level in the northern slope regions, the germination, growth and yield of Astragalus membranaceus and Digitalis purpurea were reduced by the wind. As the altitude was higher, the temperature was more slowly down in the northern slope regions than in the southern slope regions, while, the moisture was relatively high. The growth of Carthamus tinctorius, Melissa officinalis, Anethum graveolens and Angelica gigas were generally reduced by the higher altitude. On the other hand, growth of Saururus chinensis was good at the 700m above the sea level.