The grading treatment system (GTS) is considered an effective solution to defuse the antagonistic relations between the use of medical resources and the residents′ medical treatment demands in Chinese cities, as well as to ease the faults in urban ordinary medical services. Since the urban community health institutions (UCHIs) undertake the first diagnosis and transfer treatment in GTS, they are basic elements of GTS and their accessibilities ought to be accurately detected so as to evaluate the development of GTS. Therefore, the influential factors of accessibility of UCHIs are deliberately selected according to the general characteristics of GTS, and then the improved potential model to detect the accessibility of UCHIs is established with the analysis of pedestrian traffic impedance and its function range. At last, a case study of Xi′an city is done through the employment of the model established above. The research results indicate that accurate detection of pedestrian traffic impedance is the critical point for the accessibility modeling of UCHIs based on GTS, while both the road section conditions and crossing facilities at intersections contribute to the calculation of pedestrian traffic impedance. There is an unbalanced spatial distribution of accessibility of UCHIs in Xi′an downtown due to the temporary medical resources shortage during planning policies changing, the unreasonable site selection caused by the lack of land resources，and the variations of hospitalizing obstacles in complicated urban road system. It is suggested that traffic geography supports to the administrative planning of UCHIs under GTS will be gained with the help of this research.

grading treatment system (GTS)； urban community health institutions(UCHIs)； accessibility； pedestrian traffic impedance； Xi′an city