The connotation and development of circular economy and circular agriculture are illustrated from the perspective of circular economy. Take the duplicable Sino-Singapore Eco-City in Tianjin as a case to analyze the background, significance and features of building Sino-Singapore Tianjin Eco-City and point out the sustainable developmental orientation of the “three harmony and three capabilities” as well as its inspiration on the development of Tianjin urban agriculture from the aspects of water-saving, land-saving and energy-saving. Under the direction of circular economy theory, the enhancement of economical utilization of agricultural resources and resource utilization of agricultural wastes has positive effects on improving urban environment: decentralize organic solid wastes from sewage cycle system; further study the physiological and biochemical mechanism of increasing yield and income of ecological agriculture; bring urban agriculture into city land utilization planning and city development planning.