. It is a significant research subject to explore interaction mechanism between urban physical environment and population structure and to promote both of the orderly coupling and coordinated development. These studies are urgent requirement to eliminate the increasingly serious urban social problems and realize the urban harmonious development. Based on previous population censuses and community population survey data of Changchun,the authors establish an evaluation index to the coupling between physical environment and population structure according to the current development and problems of the region.Using methods of qualitative and quantitative analysis as well as grey correlative analysis,the dissertation built a correlation model and a coupling model of the interaction between physical environment and population structure of Changchun.They analyze the major factor and coupling relation between physical and population structure of Changchun,and reveal the distribution rule of the coupling between physical environment and population structure of inner spatial units in Changchun.The results show that the coupling mechanism between physical environment and population structure is impressible,population structure is closely connected with the physical environment in Changchun;but the coupling degree distribution between physical environment and population structure of Changchun presents a characteristic that industrial district and old city is high and commercial district and urban fringe is low. Inner spatial units of Changchun can be divided into four phase types which are high level harmony,amelioration,conflict and low level coupling.On the whole,the proportion of conflict and low level coupling phase are comparatively large in inner spatial units of Changchun. The authors think that the physical environment and population structure of Changchun need further coordination.