Over-current protection is a conventional protection technology in the power grid environment. In order to face the different operating mode of micro-grid, research on centralized protection depending on communication system is been paid attention to system. Extending IEC61850 standard to the centralized micro-grid overcurrent protection system, firstly, structures and algorithms of overcurrent protection were studied. Secondly, three layers structure of micro-grid communication system was proposed. Establishing Information models and information exchange models of intelligent DG terminals and relay terminals and mapping information exchange models to specified communication protocols built entire communication architecture of centralized overcurrent protection system based on IEC 61850 standard. Finally, simply application scenarios were set to explain further the whole information exchange process. Through analysis, the micro-grid centralized overcurrent protection systems based on IEC61850 can achieve interoperability and seamless integration of system.