Among the trade and business area, the informal settlements in Surabaya have developed by the low-middle class. Those people try to make an opportunity of their employment. By the economic condition and the limit of legal spaces, they tend to choose their housing location at the empty slots where one is the railway terrace. The limitedness of the space in the housing area makes household activities extend to the outdoor spaces. The purpose of this study was to show the design criteria by analyzing the potential needs and the characters that occur to improve the living quality and the open space itself. So that it would give safety uses for the people around the platform. This research uses character appraisal of the physical condition and behavior observation to see the functional form and record the activities of the people to list the particular characteristic happens in this railway terrace settlement. The result will conclude the redevelopment design criteria of open space areas around the railway terrace.