To know of the biological basic method that can improve the environment of the organisms that inhabit at Deokjin Park. We studied the flora and the fauna in Deokjin Park on June, 1996. The study was surveyed and researched according to the items floras, phytoplanktons, insects and vertebrates. The floras are composed of eleven varieties, one forma, eighty-three species, eighty-four genera and forty-nine families. In the lake of Deokjin Park, the dominant species were Nelembo nucifera and Spirodela polyrhiza. The authors thought that those species be artificially excluded in winter for the improvement of the quality of water. The phytoplanktons were composed of forty genera, eighteen families, ten orders and six classes. Among those, Anacystis(=Microcystis) and Anabaena that make eutrophication, were distributed in the lake of Deokjin Park. The fauna of insects were composed of forty-one species, thirty families and eleven orders. The authors observed seven species of fish, two species of amphibian, three species of reptile, seven species of the bird and one species of mammal. Among those, Bull-frog and Blue-turtle as exotic species must be excluded by artificial methods for the other native organisms of the lake of Deokjin Park.