This study was conducted to examine natural distributions, habitats, and morphological variations of Prunus yedoensis Matsumura. Thirty three individuals which showed various growth habitats of Prunus yedoensis Matsumura were found to growing in Mt. Halla. They are generally growing in the region of 450m to 850m altitude, where temperate deciduous broad-leaved forests are developed. Morphological variation on 18 characters in flowers, leaves, fruits, and seeds showed that most characters of native individuals were smaller in the size than those of cultivated ones although the limits of variation of the characters were somewhat wide in the native ones.