Sites and capacities of substation is one of the key issues for distribution system planning, with the influences of load reliability and network structure. Now days, more influences of substation on society and environment have been concerned by people, and substation planning must be carried out according to the corresponding factors, besides economic cost. This paper presents a new approach for substation planning. Geographical property of substation site is introduced in the consideration, which is denoted to the relationship of the site and its social, economic and environmental benefits, and evaluation system of the geographical property is constructed to form geographical cost factor. By integrating geographical cost factor into cost function, the new model has the selectivity when deciding the optimal sites. In other words, the sites must be located in feasible area. It is proved by engineering cases that the model could not only consider social and environmental factor, but also ensure economy of the planning scheme.