The life of great scholar Yag-Yong Jeong who lived at the end of the Yi Dynasty in Korea has been traced and investigated with a study of a collection of his works. Emphasis of the study has been placed on landscape architecture. The resu1ts are as follows: 1. The number of landscape gardens which were mentioned in his works was seventy-three. Among them, eleven ones were closely related to a villa. 2. He named arbors after the characteristics, features of the sites where they stood. For example, he called the arbor located in mounatinside Mountain A.hor(San Jeong in Korean, where Jeong means a arbor,) that in a forest Forest Arbor(Im Jeong), that in a valley Valloy Arbor(Gye Jeong), that along a river River Arbor (Gang Jeong),that around a pond Pond Arbor (Ji Jeong) etc. 3. There were two landscape gardens designed and constructed by him. The one was that in Mug Hyang Seo Mi Gag (Gag also means a arbor in Korean) located in Gok San Bu, the other was that in Da San Cho-Dang located in Gang Jin. The former was consist of Bang Ji(a square or rectangular pond)and Ji Gag. Many flowering trees and shrubs were planted in it. The latter was composed of Bang Ji with a island and Terrace Garden. More than twenty-six species of flowering trees and shrubs were used in it. 4. Fifty-eight species of landscape plants were referred to in a collection of his works. Among them, exotic species brought abroad amounted to thirty-five in number, and the number of species which were recorded first in literary history reached nine. 5. The number of potted trees grown at his home garden were ten. Those are; Camellia japonica Firmiana Platanifolia Gardenia jasminoides Hibiscus mutabilis Prunus mume Punica granatum Vetex rotundifolia Chrysanthemum morifolium var. Musa basjoo Narcissus tazetta var. chinersis 6. The landscape plants mentioned more than ten times in his poetical works were Salix babylonica. Pinus spp., bamboo,Prunus mune, Chrysanthemum morifolium var., Nelumbo nucifera, Prunus persica and Camellia Japonira, which implies his preference to landscape plants. 7. The great interest which he was taken in landscape plants and landscape gardens appears to result from his inborn love and Inquiry of nature, and his growth with landscape gardens from childhood.