Based on satellite remote sensing data acquired in 2005 and the ecosystem service value assessment method, the ecological service value of urban artificial forest ecosystem in south hills and north hills of Lanzhou was studied. Results indicate that the ecological service value of the urban artificial forest ecosystem study area is 15.59×108 Yuan per year. The order of service value is: recreation and ecotourism＞atmosphere adjustment＞water source conservation＞forest by-product＞erosion control＞biodiversity maintenance＞wood＞firewood. The proportion of direct and indirect economic benefits in the artificial ecosystem service value is different from that in natural ecosystem service value because the building of the ecosystem is artificial and purposive. The research is quite important in theory and reality for the assessment of the urban artificial forest ecosystem service value, and would be helpful to realize sustainable development and environment protection in western China.