To preserve scenic-view of Gwanak Mountain from the urban development, the viewshed component ratio and the scenic-view preference are investigated and analyzed by selecting view points at Nangokro. After 16 candidate view points are selected from the site, sight component ratio is measured through visual structure analysis and preference are measured by using the Likert scale. In addition, factor analysis, and regression analysis were conducted to examine the relationship between influencing factors and preference. As a result of the regression analysis of the 9 factors to influence the scenic-view preference, two factors such as degree of natural landscape and degree of arrangement around the site are chosen to influence the scenic-view preference. Through the preference factor analysis, two preference factors are selected as follows; 1) The factor of the landscape formation - Existence and nonexistence of the scenic-view conservation, degree of the landscape opening, and degree of natural landscape, degree of the landscape originality, and degree of the landscape sequence, degree of the landscape intimacy 2) The factor surrounding the landscape - Degree of arrangement around the site, degree of the landscape complexity, and atmosphere around the site.