The purpose of this study is to establish design guidelines for waterscape facilities of healing gardens in psychiatric hospitals. Data were collected through simulation and interview. The subjects included schizophrenic (n=42) and alcoholic (n=41) inpatients as well as medical staff personnel (n=40) at Maeumsarang Hospital. The results of this study are as follows: It was revealed that for all three groups the first preference was a natural flowing waterscape, and the second preference was a natural descending waterscape. The schizophrenic subjects had a greater preference for a static artificial waterscape and a descending artificial multistory waterscape than the other two groups. The alcoholic subjects preferred an ascending natural multistory waterscape. The analysis on the preference towards an ascending type and a descending type from the perspective of naturalness and complexity. Complexity had a greater influence than naturalness in the ascending waterscapes, and naturalness had more influence than complexity in the descending style waterscapes. Therefore, these factors need to be taken into consideration when designing either ascending or descending waterscape facilities. In general, the subjects preferred natural, dynamic and descending waterscapes to the artificial, static and ascending variety.