Getting surgery from dentist is the common experience of our life. But it will cause dental stress from making uncomfortable feeling in dental treatment, even let the dental clinic to become an uncomfortable environment. In recent years new methods have appeared tackle the issue of interior decoration in dental clinic. Therefore, it may change the clinic’s atmosphere and get comfortable feeling to shift the attention from dental stress. Greenery decoration is a kind of interior decoration, according to the study of Hsu, Chen & Chang (2011), they suggested that viewing the tree shade of camphor picture can reduce dental stress when patient were in dental surgery. However, the composition of nature landscape includes color and shape. Not only color, shape is also clear when people who want to determine the nature elements. There are two shapes in geometric and organic were using commonly in our life to prompt exist of nature element. Sometimes it can also prompt by taking photography to show the real nature views. The purposes of this study were to investigate the patients' stress reducing effects through views the ceiling with the four different realities of greenery decorations (pure green, circle of geometric, leafs & tree shade of camphor) in dental surgery room. Personal information, viewing times, preference and feeling were also investigated. The secondary purpose of this study was to identify the impact factors on stress reducing effects. This study was conducted at a dental clinic in Taipei. Experimental materials were putting on the ceiling. The questionnaire consists of five main parts. Participants rated three perceived effects of dental stress: pain relief, fear relief, and tension relief. Besides, their viewing times, preference, feelings and experience of viewing about the greenery decorations, as well as personal information were also collected. Exclude participants who have multi-viewing experience, three hundred and forty six patients viewed the greenery of four different ceiling wallpapers when they received dental treatment. The results revealed that viewing the four greenery decorations all can reduce dental stress and have significant difference between pure green picture group and control group on patients' three perceived effects of dental stress reduction. However, viewed the other three picture groups can only reduce the fear relief and tension relief significantly. In addition, gender, age and viewing times of participants were not the impact factor of these stresses reducing effects on experimental group. The respondents' preferences of the four greenery decorations were very high. Regarding the feelings of viewing greenery decorations most of them were positive, such as relaxed, comfortable and natural fresh. It indicated that uses color tone of green can receive same high positive feeling in hospital’s interior decoration. The result of this study could be useful to those who are responsible for designing interior decorations in hospital.