Soundscape is about relationships between the ear, human beings, sound environments, and society. Soundscape research is interdisciplinary. On the basis of a series of case studies in Europe and China and an intensive literature review, the soundscape description, evaluation, and creation in urban open spaces are systematically examined, in terms of four basic elements: sound, space, people, and environment. Factors affecting soundscape evaluation in urban open spaces, including acoustic - psychological - social characteristics of various sounds, acoustic effects of space boundaries and elements, social - demographic characteristics of users, and general physical - environmental conditions, are identified, and, consequently, a system for soundscape description is established. Potentials of creating and designing soundscape in urban spaces are then discussed in terms of sound and space.