Abstract: The Urban afforestation is the Urban ecosystem important constituent, deepens unceasingly along with the Urban pollution degree, the Urban afforests in improves on the Urban ecological environment and the landscape plays the vital role. The Urban afforests should comes the science according to the Urban ecosystem characteristic and the principle to afforest, this summary from the afforested species vegetative form choice, the ecotype choice, the resistant species choice, the vigilant biological invasion, the spatial pattern constructs and the seasonal aspect suitable and so on various aspects carries on the analysis to instruct the Urban to afforest, and requests to its scientific management, achieves the Urban sustainable afforestation goal..