With increasing academic research in the past few decades, the knowledge scope of landscape architecture has expanded from traditional focus on aesthetics to a broad range of ecological, cultural and psychological issues. In order to understand how academic research and knowledge expansion may have redefined the practice, two surveys were conducted: one on Council of Educators in Landscape Architecture (CELA) in 2010 (n = 230, response rate = 43%), and another on the members of American Society of Landscape Architect (ASLA) in 2012 (n = 239, sample rate = 5%, response rate = 31%). Results revealed that the scope of knowledge has expanded since 1970s in areas such as public welfare and personal pleasure. 2) The need for academic research is widely perceived in landscape architecture profession. 3) Academic research primarily generate explanatory knowledge, which has become an important supplement to judgmental design knowledge learned through systematic professional education and construction design knowledge learned through practice. 4) Practitioners believed that they use more logic thinking than intuition in their practice today, and expected more research to facilitate the former than the later.