The demand characteristics and design principles of cement enterprises in the progress of energy management system construction were systematically analyzed in this paper. The design scheme of energy management system based on OPC technology and.NET multi-layer architecture was proposed besides. The principle of system design, the compositions of the hardware and software, and the function features were introduced. The system could share data resource with DCS, and waste heat generation system, and thus could provide global energy balance analysis. Accordingly, the system is useful for reasonable energy utilization and energy saving.