This study tries to promote an effective use of semi-public space of urban street in social point of view. The main results are follows. First, semi-public space is occupied by private users and it makes urban landscape unrecoverable. The real problem is that people do not know the space is for public use rather than pure private use. Second, the standard of semi-public space requirement should be changed from floor space to lot area. In addition, the standard should apply to buildings on an area less than a legal standard. Third, some ways of attaining the semi-public space in relation with adjacent lots should be introduced in the case of urban redevelopment nad living condition improvement projects.