Urban forest is usually referred to vegetation growing in urbanized area or areas influenced by urban activities. Generally speaking, urban forest could be divided into such three parts as central urban forest, periurban forest and exurban forest. Urgently demand for trees management and concerning with urban landscape and citizens living quality resulted in conceptual formation of urban forestry based on integration of urban forest and urban ecology since 60s of this century. Urban forestry pays more attention to structure, function, boundary, gradient and linkage of urban forest ecosystem, to ecosystem management, land utilities and spatial distribution of benefits and costs; and to participation and disturbance of mankind. Urbran forestry aims to construct safe, beautifying and effective urban forest so as to improve local environmental quality. Meanwhile, urban forestry tries to provide an ecosystem management approach for dealing with relations of human beings and natural resources, of environmental conservation and developmental construction. Urban forestry makes an attempt to understand social and ecological values and common well-beings characteristics of urban forest. This paper tries to discuss about the principles and practices of urban forestry, and to promote development and application of urban forestry in China.