In cable trench construction, one of the tasks for engineers is to select a suitable route to minimize construction cost and obstructions. This paper discusses the development of a Geographic Information Systems (GIS)-based Customized system to automate the process of optimum shortest path finding for routing of underground power supply cable between any two substations. It combines the spatial analysis capabilities of GIS with the sophistication of one of the Artificial Intelligence technique "Simple Ant Colony Optimization" to deal with the complexity inherent in optimum shortest path finding. The results of this project are validated and compared with an inbuilt tool Network analyst of GIS software ArcGIS and explained in the Result and discussion of this paper. In this project only optimum shortest path finding is aimed and this will be one of the main input data in my future work of improving distribution efficiency using GIS. © 2005 - 2014 JATIT & LLS. All rights reserved.