Smart growth is accepted by most scholars in the developed countries. The paper reviews the previous attempts to define and measure urban sprawl, studies measuring sprawl and relating it outcomes, studies measuring sprawl and exploring causes, studies on urban form and studies on smart growth management. And then some suggestions, which content and method of research on urban sprawl tends to be perfect and measures are more and more exercisable as well as pertinent, are put forward. Now urban development with character of low_density land use pattern has have been in China. The research on urban sprawl in Western countries can be used for reference.