OPC is the preferred communication standard for sharing process control data at all levels of the enterprise and becomes the global standard, sends/receives the data with PLC programs of inspection system via network, and manages various data using OPC server. In this paper, we introduce the developed OPC client system for FPD inspection system with OPC server. To control inspection system through OPC server, we have developed libraries which consist of stage driver, switch driver, microscope driver, image processing, alignment, and task management modules. Also we have developed the test program to verify all functions precisely. We describe the mechanism of inspection system, OPC connection method, and programs.