A result of development of computer technology, geographic information systems (GIS) is now being used in the operation of power distribution systems. GIS is a special-purpose digital database in which a common spatial coordinate system is the primary means of reference. Comprehensive GIS require a means of: data input (from maps, satellites, surveys, and other sources), data storage, data transformation, analysis, modelling, and data reporting (such as maps, reports, and plans). This paper presents a new methodology for perform distribution operation based on GIS. It uses a programming model for power distribution's dynamic data. This model, using static network information (network location, path lines, and geographic conditions) and the use of dynamic information network (at the moment, line voltage and current) will apply to the computation time. Customer's loads is calculated. By the proposed method, using the program modules, the customers load can be updated according to load balancing. To demonstrate the effectiveness of the integrated GIS system with application programs for distribution operation, a zone at East Azerbaijan electric power system distribution Co. is selected as a real case study.