(Abstract) The purpose of this study is to examine the contents of poems and letters related to the land left by Toegye in his lifetime and from this point of view the study was focused on getting what is the land thought and space consciousness of Toegye, and further the study is aimed at contributing to the cultivation of human nature lacked in modern people by suggesting an educational implication according to the conclusion reached. In order to accomplish the purpose of this study effectively, the study realm was made for the time period from the year 1501, when Toegye was born, to the year 1570, when he died. In terms of the spatial realm, it was focused on Gyeongbuk Andong-gun Yean-hyeon Ongye-ri Jisanwasa, Yangjinam, Hanseoam, Gyesangseodang and Dosanseodang. In terms of the contents, questions were made about what the educational implication of the land thought and space consciousness by Toegye stands for. The findings support that the first the land thought of Toegye is come from the fact that all things are created from the land and indeed the land and human beings are one body(地人合一體思想) because the land is a mother as a source of all things. Second, the land thought appeared in the letter of Toegye is related with "The Land-to-the Tiller" thought(耕者有田思想) in which the land was regarded as a public property(共有物) based on the idea of "The Land and Human Beings are One Body" Third, the land thought appeared in Seowongi elaborated that a great person is come from the land soul(人傑地靈思想) and as Toegye claimed a place situating superb natural environment or a place producing a noble scholar with good learning and virtue has a land soul. Fourth, as for the land thought appeared in property management, Toegye, a classical scholar, regarded the land as an object simply to produce foods requiring for a means of living, not for increase in property and not for preserving its value, when it comes to cultivating or buying land, worrying about contamination of land or protecting from being contaminated. Rounding out Toegye''s fragmentary thought of the land as suggested above, the ultimate thought of the land is summarized with an idiom that the land and human beings are one body(地人合一體思想). The following is the study result of what the space consciousness of Toegye stands for: First, Jisanwasa is a place where Toegye lived for about 3 years until he went to Hanseong in April 1534 after he got married and this place became a main post for him as a space for reading books to prepare his future. Second, Yangjinam was a temporary abode completed in November 1546, the hard time of Toegye, and it was less than a year for him to live at Yangjinam. However, Yangjinam played a major role for Toegye as a resting place to recharge his mind and body when he had hard time. Third, Hanseoam was a place where Toegye settled at the age of 50, and if Yangjinam was a place for his resting, Hanseoam could have played a major role as a self-discipline or mind control space(?神養性) for healing one''s weak mind. Fourth, Gyesangseodang was a place where Toegye named it Seodang for the first time and he regarded it as a space to complete 5 precepts(吾事) in lifetime. However, Gyesangseodang had some limits for the self-discipline space due to such poor environmental conditions as its steep terrain, narrow house and inaccessible city during flood but played a major role as an educational space. Fifth, Dosanseodang was a place where Toegye settled down his life by taking advantage of his long experiences for the residential space since then. Thus, Dosanseodang played a role as a comprehensive education space such as reading books space, resting space, self-discipline space and education space. Rounding out Toegye''s fragmentary thought of the space as suggested above, the ultimate thought of the space is summarized with an idiom that "space, land and human beings are one body(天地人合一體思想)" in which "Space(天)" is added to the idiom that "the land and human beings are one body(地人合一體思想)", an idea of the land. The educational implications of the land thought and space consciousness by Toegye are as follows: First, the main reason that Toegye tried to quit his government position and return home was to prepare his 5 precepts. Then, why did Toegye try to prepare 5 precepts in a primitive forest space commanding beautiful landscape? It was because of his intention to train the right talented people based on his thought of the land and space consciousness and because Toegye regarded the cultivation of human nature as a product come from the natural space. Thus, it reminded us a true education should be possible when the education in the education space and the activities in such a self-discipline space were harmoniously combined. So, the educational implication of the reason why Toegye tried to quit his government position and return home tells us the experimental education by the nature in the natural space is an alternative way to the education mainly with knowledges in a school in order to prevent many different crimes caused by lack of human nature that the modern society has faced. Therefore, in order to cultivate the human nature which is the core competence of the future society, it is necessary to think of how the natural space can be secured in the current educational space or how to be able to carry out more education activities by nature in the natural environment. Second, the reason why Toegye had built a house and moved frequently was to locate the best land conditions to achieve his own 5 precepts. Toegye adopted a place where natural environments with beautiful landscape showed up and the hometown of a scholar with his/her good learning and virtue or a place having much more learning and virtues as the best land condition, based on the thought that a great person is come from the land soul(人傑地靈思想). The educational implication to this end suggests that it is necessary to secure natural space first rather than modernization of the current educational space in order to cultivate human nature since the self-discipline education is available only when it is mixed and harmonized with the nature in natural space although the pursuit of study and education can be done in an artificial environment. Third, the significance of 5 precepts pursued by Toegye in his lifetime was to cultivate lots of decent people so that they will make the right world. After all, the reason why Toegye tried to quit his government position and return home was to make the right world by producing lots of decent people in such an educational space with the best land conditions. The educational implication in this respect tells us that the modern education should nurture talented people who are cultivated with human nature, which is the core competence of the future society from a long term point of view, rather than cultivating packed talents aimed at memorizing education mainly for examination and employment. To this end, discussions about the society at large including the issue of the entrance examination and employment standards should be secured.