The purpose of this study is to suggest optimum level of the Ratio of Greenery within the frame of vision in the interior landscape design through the analysis of visual character and preference of the interior landscape. The concept of the RG was defined as the ratio of projected area of plants higher than 1.2M against background wall from eye level. 5 photography of Interior landscape space -- 10,20,30,40 and 50% of the RG-- were constructed by computer graphic techinques. Likert scale and semantic differential scale were used to analyse visual character and preference of the interior landscape space. The analysis results are as follows : 1. Factors that compose of the image of the interior landscape have been found to be the "evaluation ", "complexity". The mean value of semantic differential scale showed a significant difference according to RG. When the RG was 20~30%, "Harmony" and "stability" was strongly recognized than the other factors and the interior landscape made the interior space natural and intimate. But at the RG 40!50%, users felt "stuffy" and "too complex" by many plants, so it was not efficient the Interior Landscape. 2. The visual preference was significantly different according to RG. The mean value of the visual preference was increased as the RG was higher, it was the highest at the RG 30%. But over the RG 30%, the preference level was declined. 3. Based on these results, this study suggests that the optimum level of RG in the Interior Landscape is 30%.at the optimum level of RG in the Interior Landscape is 30%.