"Introduction The person takes the behavior corresponding to the impression that formed beforehand (Asch, S.E., 1946; Kelley, H.H., 1950). This suggests that preliminary knowledge to the person influences the behavior. The suggestion would be able to replace process to constitute the image of the urban environment. Kevin Lynch shows that "Meaning" is one of the components constituting the image of the city, and that the public image in common to the urban environment exists (Lynch, K., 1960). However, it is not clear that preliminary knowledge could be influenced to cognize urban environment. Purpose The purpose of this study is to clarify the influence of preliminary knowledge to cognize urban environment. Method This is experiment through wayfinding behaviors. The proving ground is one block constructed on grid network of streets. The experiment is conducted twice with the same proving ground. The subjects are twenty persons, and they do not have the direct or indirect knowledge about the proving ground. The first time is investigated by ten subjects who are not given preliminary knowledge, and the second time is investigated by another ten subjects who are given preliminary knowledge. The preliminary knowledge is the five concepts including the history emphasized than the reality. These concepts are "General form", "Constitution of the street", "Physical element", "Transition of time" and "Atmosphere". The procedure of the experiment is as follows. The subjects walk around the proving ground. The subjects walk freely from the center of the proving ground, and finish wayfinding behaviors when the subjects can cognize the proving ground. During wayfinding behaviors, the walk trace recorded. After the end of experiment, the subjects are classified by Cluster Analysis based on the walk trace. The subjects are interviewed about process to cognize urban environment. The contents of verbal communications and the number of persons based on verbal communications are extracted to clarify the tendency to the concept through the interview. Results and Discussions The number of persons based on verbal communications to "Atmosphere" has more the subjects who are given preliminary knowledge than the subjects who are not given it. In addition, most of the subjects who are given preliminary knowledge walk a long distance. On the other hand, the number of persons based on verbal communications to "General form" and "Constitution of the street" has more the subjects who are not given preliminary knowledge than the subjects who are given it. In addition, most of the subjects who are not given preliminary knowledge walk a short distance. Therefore, according to the influence of preliminary knowledge to cognize urban environment, "Atmosphere" such as feeling the history is emphasized, and forms and constitution such as "General form" and "Constitution of the street" are not emphasized. "