Energy management system（EMS）application program interface standard IEC 61970 makes the power system automation development towards integrating and networking. Expanding common information model（CIM） based on IEC 61970， the concept of branch for modeling of different applications like photovoltaic， wind power， energy storage， etc.， is proposed. Then the concrete CIM for microgrid with low carbon and high efficiency is built， which constructs the integrated information model of microgrid. It is also introduced into microgrid EMS design and provides the unified interfaces for further developing advanced application program in microgrid EMS.