Psychiatric hospital gardens should be designed as Open Space Therapy Units to provide contributions on treatment process. However assessment of recuperative effects of these units on patients is not easy. The researchers state that so many resources (Ulrich, 1999), elements (Marcus and Barnes, 1999), factors (Kaplan and Kaplan, 1989), patterns (Kaplan et all, 1998), and components should be in these areas. The theories of Ulrich (four resources), the Kaplan’s (factors and patterns) and Marcus and Barnes (elements) are summarized by three restorative experiential qualities (sensory stimulation, movement and control) by help of litterateur in this research. Four landscape design attributes (enclosure, water, spatial configuration and materiality) are identified to the restorative experiential qualities found in these areas. In addition, it is explored the connections between these four design attributes and the three restorative experiential qualities in this research. Thus, this study could be used for determining the effectiveness extends of an open area for being a therapy unit. And for demanding an open area therapy unit, which should include necessary landspace design attributes and experiential qualities and properties.