A number of illustrated floras are generally used when we want to identify a name of a certain tree. This method, however, has not been efficient because it has taken a great deal of time and effort for persons who do not have much knowledge on the group of the plant. In contrast to this method, the use of taxonomical keys is very efficient for finding out the group of a certain plant. But this method is very difficult for non-specialists to understand the taxonomical terminology and thus has not been of general use. In this context, this study was conducted to present the efficient way of identifying the group of a certain tree through the computer database by using the brief forms of plant organs. The database consists of eight fields such as form of trunk and evergreen or deciduous, types of leaf and leaf arrangement, existence of prickle and hair on twig, form of leaf margin, leaf form and venation, existence of hair on leaf surface and petiole, length of leaf and petiole. The 222 species of tree used for landscape architecture were sorted by items of the eight fields. As a result, the 222 species were divided into 185 groups and the one group contains 7species, 2 groups contain 3 species, 27 groups contain 2 species and 155 groups contain only one species. Therefore it is suggested that the use of computer database and illustrated floras is very easy and efficient in identifying a tree.