To support plant operators to operate and manage the plant for better quality, safer, and less cost, this paper describes the design and implementation of an intelligent Graphical Engineering System - iGES. First, three types of functions, data management, problem solving and utilities, are designed to support the whole plant operation. Then, a distributed and integrated software system architecture is described. Within this architecture, a central platform manages the functional distributed components, in terms of data transfer and communication and interfacing. Finally, the implementation issues are discussed in two phases including technical and business decisions, current status and next step plans. Based on a few commercial packages, the first phase system has been implemented and installed into a project site for evaluation.