The Daejeon station plaza, created by the construction of the train station in 100 years ago, is a popular public space in Daejeon. The plaza is facing transformation by the redevelopment of Deajeon station areas. For generating the satisfied results, design references should be provided to guide redevelopment in terms of functional effectiveness and cognitive preferences. This study aims at proposing appropriate design guidelines for the plaza. Utilized data here were collected by literature review, a case study, unobtrusive observation, and an interview-questionnaire survey. The results of the survey were analyzed to evaluate the degree of significance regarding the development of Daejeon station plaza from two groups: (1) total 749 interview-questionnaires from the general public and (2) total 50 interview-questionnaires from architectural/urban design experts. This study found that the Daejeon station plaza is mainly perceived as a functional traffic plaza. Specifically, the public group preferred an emotional development approach to rational one, showing preferences to environment plaza rather than traffic plaza. Comparatively, the expert group perceived the important role of Daejeon station plaza as a traffic plaza, while emphasizing the role of environmental plaza. In conclusion, the Daejeon station plaza as a public space has various usage and meanings among users, demanding careful design consideration to bridge preference gap between design experts and non-experts.