The purpose of this thesis is to suggest basic objective data for landscape planning and design through the quantitative analysis of the visual impact of pavilion situated in natural landscapes. For this, naturality and visual preference scores of landscape s1ides were measured by questionnaires, visual volumes of pavilion in the natural landscape were evaluated using the Mesh analysis and images structure was analyzed by the factor analysis algorithm The results of this thesis can be summarized as follow. Landscape slides No. 27 and 9 were ranked more highly for naturality, and slides No.22, 28, 6 and 4 were ranked more highly for visual preference. Factors covering the spatial image of the natural landscape were found to be the evaluation, the tidiness and the space volume. By using the control method for the number of factors, T. V., were obtained as 59.0%. For all experimental landscape slides, the factors of evaluation and tidiness were found to be the main factors determining the naturality and visual preference. The naturality and actor scores and the visual preference and factor scores were found to exepress the regression relation.