Cities are not always growing. In particular, population is likely to peak very soon and socioeconomic activities are inclined to agglomerate in several regions. Under these circumstances, some cities have faced population decline, which is an irritable trend for both the world and China. More and more developed countries are facing the increasingly severe shrinkage in cities, and this phenomenon triggered a series of complex social problems. Western countries had studied extensively about the issue of shrinking city, but in China, the study of shrinking city is still in a shallow stage. Drawing on very recent studies on urban shrinkage, the paper introduces the definition, origins and phenomena of shrinking cities. For the cities facing the population loss more than two years, and undergo the structural economic crisis, we could call them "shrinking city". It divided the reasons of shrinking to three causes, de-industrialization (mostly in Britain), system adjustment (mostly in Germany) and suburbanization (mostly in America). It further described the process and influence factors of urban shrinkage. To be specific, the paper considered the factors influenced shrinking cities are the adjustment of economic structure, the change of the social population structure, the change of urban spatial structure, resource depletion and political factors. Urban shrinkage process cannot be planned, so the policy decisions is naturally unpredictable. Moreover, urban shrinkage process and performance in different cities show different phenomenon and levels. Furthermore, by introducing the response from foreign countries, including aspects of land use, life quality, managing strategy and planning practice, this paper shows a multiple choice for Chines cities which are experiencing or about to experience Shrinkage.